MinoPropertyMidiChannel: new property to select MIDI channel

This new class will be used by MinoInstrumentedAnimation to handle channel selection.
UiAnimationProperty: UI representation for newly added MinoPropertyMidiChannel

This graphical implementation is based on QSpinBox UI object.
MinoInstrumentedAnimation: add MIDI channel filter

Use of MinoPropertyMidiChannel and filter received notes depending on user selection.

This patch broke compilation, classes based on this virtual class need update
MinaFallingObjects: implements new note filtering method
MinaRandomPixels: implements new note filtering method