Fixed firmware bug, genericised baud rate for CFIDE for debug-over-MIDI.

MIDI now working on V1 and V2 hardware.

Updated firmware, reversed sense of menu buttons.

Added not gates to sync signals, since the Chameleon has external tra…

…nsistors on these lines which invert the signal compared with the original Minimig.

Re-enabled usart rx, reconfig now works when core is launched from JTAG.

Fixed a slot-overlap bug, changed SDRAM clock phase shift a little.

Fixed major RAM aliasing bug - 24 meg should work properly now.

Changed background colour of file selector.

Reverted address-mangling change since it turned out to be counter-pr…

…oductive.

Got a simple single-word write buffer cache working.