initial pass of MIDI implementation that bubbles events to JS
add the ModWheel property to the MIDIManager
resolve conflicts on merge with upstream master
Merge branch 'master' of https://github.com/highfidelity/hifi
add the PitchWheel constant to the MIDIManager class
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge branch 'master' of https://github.com/highfidelity/hifi
don't require RtMidi if it isn't present
Merge pull request #3113 from birarda/master

initial pass at MIDI input for scripting