Currently only supports one Mockingboard in slot 4, but it should be
fairly trivial to add another in slot 5. Tested with Ultima 3, 4 & 5,
and Mockingboard disk #1. Also, added some fixes to correct the timing
of the 6502 and sound; I believe I have a good understanding of it now,
even though there's still work to do to keep the main CPU thread from
starving the audio thread (which still happens, but less often now).
The keyboard handler now properly emulates the //e's 2-key rollover.
However, we might have to add in a key repeat delay if it makes it so
that you can't type on the console anymore. This had to be done because
SDL will throw in key delay if you rely on it's SDL_KEYDOWN message and
this caused many games with keyboard input to be unplayable. Also, we
consolidated the video handling files, as there was very little in
video.cpp and so we moved it into applevideo.cpp and renamed that file
to video.cpp. Things are a lot cleaner as a result of this merge. :-)
The idea is to present icons for the most commonly used functions that
will pop up on the screen when moused over, then go away once the mouse
is not over them anymore. Hopefully this will actually be usable, unlike
the previous clusterfuck that I attempted. It was a good idea, but SDL
just wasn't up to the heavy lifting required.
