lots of changes

* remodeled sysex response function - much simpler now
* buttons and pots are now fully configurable via sysex
* remodeled LED code - constant and blink state are now handled via same
note, only with different velocity (0-62 constant, 63-127 blink)
* seprated led notes (MIDI activation notes) and led numbers (only used
for start-up)
* code now checks EEPROM for ID bytes on startup - if they're not found,
it will overwrite entire EEPROM with OpenDeck default configuration
* added AU-123 MIDI PCB and gerber files
* moved circuit to schematics