Consider reworking script editor to have plugin-based editor panes

[hinerm]

Currently the SriptEditor/EditorPane are fixed towards the "run the whole script" paradigm.

It would be awesome to have EditorPane detection be plugin-based based on script language handling - e.g. open a Java script and get the classic "run" = compile and run the whole script editor, open a clojure script and get an interpreter.

This could also help us decouple script language support from the Swing-specific code.

[hinerm]

@kephale suggests that it may be as simple as changing how the editor responds to "enter" - sending the current text to the script engine or not.
And then we would need to expose lower level functionality about whether or not the engine should retain state between runs..