enable MIDI channel reprogramming via sysex

* MIDI channels are now fully reprogrammable via SysEx messages
* rewritten parameter check function for sysex - it now enables checking
of new parameters as well, if sysex message is a setter
* added basic (only ID check) and extended length of sysex message in
SysEx.h
* added NUMBER_OF_MIDI_CHANNELS, NUMBER_OF_HW_P, NUMBER_OF_SW_F and
NUMBER_OF_HW_F so that it's easier to check for whether all parameters
are stated in sysex "set all" message
* better determination of minimum sysex message lenth
* better error checking
* formatting
* misc