Tap tempo updates:
* catches accidental multiple-presses
* asterix displayed on screen to show feedback as tapping
Virtual port renamed to 'Live-MIDI-Player'
Note-off's quantised to sub-beat before
* to avoid the same note being cancelled-out by a similtaneous on and
off
Mute groups now work by channel rather than by group
MIDI output now connects to first available device automatically
(required for Windows which doesn't support virtual ports)
Control track now optional
When song loaded, all tracks are now combined into one array