Add some minor comments
MidiInterface: renames sendMessage() to sendControlChange() when relevant
Ui: remove (commented out) "MIDI learn" button as it cant be used
MinoTrigger: new connect/disconnect feedback function

This patch allow MinoTrigger to disconnect connected signal properly
MidiMapper: connectTrigger() now returns corresponding MinoTrigger
MinoMasterMidiMapper: introduce virtual pages

This implementation allow to scroll within tracks (animations groups in program) using 2 buttons (increment/decrement).

This have been tested using nanoKontrol 2 with LEDs feedback.