midi: Substantially improve decoding of MIDI messages.

midi: Substantially improve decoding of MIDI messages.

 * Decode note names and percussion names (ex: 'G2', 'Tambourine').
 * Decode instrument names and drum_kit names (ex: 'Flute', 'GS Orchestra Kit').
 * Handle Polyphonic Pressure / Aftertouch (message 0xAn).
 * Handle Program Change (message 0xCn).
 * Handle Channel Pressure / Aftertouch (message 0xDn).
 * Handle Channel Mode (message 0xBn mm where mm is 120 through 127).
 * Handle System Common messages (message 0xF1 through 0xF6), including
   full time code decoding.
 * SysEx decoding now decodes the 1-3 byte manufacturer field, payload
   is now displayed as hex.
 * 'undefined' fields now display the value (ex: 'undefined 0xf4').
 * Add 'MSB' and 'LSB' to many control_functions entries.
 * Fix "trapped in state X" bug with handle_channel_msg_generic(),
   though this might be dead code.
 * Fix bug in sysex_manufacturer_ids; 1-byte manufacturers were not
   tuples due to missing comma.
 * Fix bug in SysEx decoding state machine; 0xF7 now sent to handle_sysex_msg().