Merge pull request #47 from teotigraphix/master

Added [Shift + Master] to enter Bitwig perspective/panel toggle mode
Implemented long press for master button.
Refactoring Push modes into separate files/classes
Added activeMode to Push
- implemented activeMode in Push.control updateDisplay()
Added isFullDisplayMode() to Push for modes that require a full display
without the Track footer
Refactored BaseView.onValueKnob() into Mode subclasses
Refactored onFirstRow(), onSecondRow() out of BaseView
Removed global mode variables from Push.control
Updated contribution headers, added missing liscense headers