Add borders (color background) option

[SopTheSop25]

@carmiker

Borders (Color Background)
Enable this to display the overscan regions at the top/bottom and/or left/right of the screen. These would normally be hidden by the bezel around the edge of a standard-definition television

OFF

Left/Right

Top/Bottom (NTSC/Famicom mode)

Top/Bottom (PAL/Dendy mode)

Full (NTSC/Famicom mode)

Full (PAL/Dendy mode)

[carmiker]

It's not out of the question, but this is fairly low priority. The major focus of my work on Nestopia will be passing all of the TASVideos accuracy tests.