Add culling, add .schem import and export, add golem geometry

• Implemented the geometry for copper golem statues, but not the textures. The textures are pretty elaborate, and I may simply not do them.
• Added Sponge Schematic v3 (.schem) export and import, via Open. The older v2 format is also read (but not v1 - it's rare; let me know if you encounter it). The legacy MCEdit .schematic writer caps block IDs at 255 and loses 1.13+ blocks; the new format uses Minecraft's modern string-based palette (e.g., minecraft:oak_log[axis=y]) and round-trips through WorldEdit, FAWE, Litematica, and Axiom. Issue #40.
• Added Culling Schemes, and removed Color Schemes. Similar to Color Schemes, with a culling scheme you can choose any blocks you want to be culled out (invisible). Works with modern block IDs, unlike Color Schemes. (Thanks to rainbow-krash for this suggestion.)
• Torchflower export was choosing the wrong texture, closed eyeblossom. Fixed.
• Other small fixes, such as correcting colors, lighting, and names for blocks, and Block Test World cleanups.
• Update Dokucraft terrain files to their latest, 1.21.11.

Added Recent Exports, piping/headless, Jump to Player fix, and more

• Fixed "Jump to Player" a bit. The previous version jumped to some location the player had been, instead of the current location. Should jump to the current location now. If there are multiple players, one random player is chosen, I guess.
• Implemented the ability to pipe data into Mineways in a "headless" mode. See scripting for documentation and examples. Issue #49. (Thanks to TheDuckCow for this suggestion.)
• Fixed USD export name collisions in the mesh block library: when many blocks were exported, multiple USD mesh prims could end up with the same name, which caused Blender's USD importer to drop the mesh library and materials and load only the point cloud. Every emitted USD mesh now gets a unique numeric suffix. Issue #146. (Thanks to zNightLord for reporting this bug, and to Fingie for help diagnosing it.)
• Various fixes to problems found in ChannelMixer (now version 1.22).
• Fixed Tilemaker (now version 3.29) miscount of chest tiles used, issue #160.
• Added a "Recent Exports" submenu under the File menu, listing the last five successfully exported model files. Click an entry to re-open that export's settings (the same action as File > Import Settings). The list is persisted in the registry across sessions, deduped, and self-cleans entries pointing at files that no longer exist. Issue #138.

21.6 update and better exporting for various modes

• Update to Minecraft 26.1's new file format. Add golden dandelions.
• Blender import and individual block export work better with separate types, so the "Make groups objects" export option is now on by default. Tooltip also corrected.
• Export better block colors when "solid materials" export is chosen. Issue #148.
• For mosaic (3 texture) export, if PBR textures are available, also export mosaics for these, for OBJ and USD file formats. Issue #155.
• ChannelMixer and TileMaker updated. Custom texture packs updated.
• Typo fix in warning pop-up, "that" to "than". (Thanks to ilovesoggycate for the bug report.)

Most of 1.21.9 content and numerous little fixes

• Mostly update to 1.21.9. Copper golems will get added eventually (maybe...), but they're a bit more complicated. All the rest are in: copper bars, chains, lanterns, torch, lightning rods, chests, and shelves.
• Modify USDA lighting and emission values to better work in Blender.
• Remove Omniverse Composer documentation, as that product is now unavailable.
• Fix long-standing 3D print bug: wheat and nether wart blocks now properly choose the right textures. (Thanks to Alek Broman for the bug report.)
• Better information for mesh repair if detailed blocks are turned on for 3D printing.
• Add "iron_chain" as another name for "chain", a change in 1.21.9.
• Avoid crash on "impossible" data, such as redstone wires hanging in space. (Thanks to Fhxa3 for the bug report.)
• Comment out first line in OBJ material file, "Wavefront OBJ material file".
• Change USD mesh normal interpolation from "faceVarying" to "uniform", on the advice of Jesse Y.
• Other little cleanup fixes, such as properly clamp tiling modes for all chests.
• Avoid warning in ChannelMixer about texture decorated_pot_base.png not being used - it is used.
• ChannelMixer is now release 1.20, TileMaker is 3.27.

Fix spawn reading for 1.21.9

• Read in new spawn location format introduced in 1.21.9 (sorry, no new block support for 1.21.9 yet!), and give only a warning if this read fails (Thanks to Mike and Cathleen for reporting this bug.)
• Warn if new format .schem file is encountered on drag and drop, and properly warn if a .schematic file is corrupt when loaded by a script. (Thanks to Alexandru Cioc for reporting this bug.)
• Warn if the "region" subdirectory for data does not exist, and give guidance if WorldTools might be used. Added to docs how to use WorldTools for grabbing server-side world data and use it in Mineways. (Thanks to chim-pan-zee for reporting this bug.)
• Fix 3D printing "noise textures" export so that it uses the material generated properly. (Thanks to Andy for reporting this bug.)
• Protect a bit better against illegal 3D printing option combinations. Still a bit wifty. (Thanks to Andy for reporting this bug.)

1.21.6 dried ghast added, and small fixes

• Added 1.21.6 blocks, i.e., the dried ghast.
• Avoid bad states between various export modes when exporting. Toggling "Export lesser, detailed blocks" put fatten and simplify mesh into meaningless states. The whole system could use a redo, but this fix should avoid some bad combinations.
• For material counting, change to a resizeable list, as the number of materials can get extremely high under certain circumstances (including individual block export).
• Fixed (more or less) for USD export multiple materials output with the same name, when exporting using the three-texture option. Warn user away from using this option with USD export. See issue #146 for more details. (Thanks to zNight for reporting this bug.)

Remove hidden polygons, turn off illumination from budding amethyst

• Fix snow (and many other partial blocks) so that rectangles that are not visible from the outside are properly culled. Previously only half of these partial-height vertical rectangles were culled. Testing a snowy mountain, this led to a 12 percent reduction in the number of triangles output, with no visual difference. (Thanks to ilovesoggycate for reporting this bug.)
• Fix Budding Amethyst so that it doesn't emit light. (Thanks to ilovesoggycate for reporting this bug.)
• Note that Fusion 360 can be used to clean up detailed Mineways models for 3D printing.

Fix leaf litter and wildflowers for Blender import

• Fix leaf litter and wildflowers so that they import properly into Blender. Note to self: the bug was caused by the wrong typeForMtl value for each in tiles.h. (Thanks to Licy for reporting this bug.)
• Adjusted leaf litter default color to be a bit brighter, so that it matches the Plains biome color.

Spring to Life update

• Added 1.21.5 Spring to Life blocks.
• Creaking heart states added, textures renamed to latest 1.21.5 versions.
• ChannelMixer 1.19 and TileMaker 3.26 now ignore any directory named "item". This is to avoid examining the various textures in "textures/item" that use texture names that are also used in some texture packs as alternate names.
• Updated texture terrain sets for JG-RTX, Doku High and Light, and LunaHD. Only the Doku sets have 1.21.5 replacement textures at this time.

Fix isolated fences and vines over blocks

• Fixed fence post bug, where a single isolated fence post would generate four connector fences. This bug was introduced when I addressed the vines problem reported by MiniRehvaro in 12.03. (Thanks to The Abyssal Enderling for reporting the fence bug.)
• Vines also had a problem, with the bottom vine face not showing up in the (rare) case where the top vine face in the block itself (which actually shows up as a "bottom" below the block above) is also generated. Rare, but fixed.