Investigate "high res" CHIP-8 mode (64x64)

[jon-axon]

Original CHIP-8 display resolution is 64 x 32 pixels, while SUPER-CHIP is 128 x 64 pixels.

However there is apparently also a "high res" CHIP-8 mode in-between the two, at 64 x 64 pixels.

The origin of this should be investigated, and an assessment made as to whether it is worth adding support for this mode into Chipolata (and how difficult or otherwise that might be).