Various compatibility fixes

[FeralChild64]

Highlights:

• screen editor fixes and optimizations
• new keyboard scanning routine, more configurable, should be more compatible - but does not support roll-over, old routine is still available as build option
• a lot of new stubs, some compatibility hacks; FileBrowser64 works now
• versioned development builds, Kernal panic screen if using mismatched ROMs

[edit] Blog post in the works.

[gardners]

Any new matching strings explained? When done, then I'm cool for it to be merged. Again, great work! Paul

[FeralChild64]

All above 3 bytes are explained: in the last commit: https://github.com/FeralChild64/open-roms/commit/28d0fa5ecf85131beeb4d3b95b5c4f142ab90cf4