MIDI messages on OSX

[pauloord123]

I found out that in OSX (Mojave) midi messages, send by QMidiOut::sendMsg(qint32 msg) are not always interpreted by the receiving device:
the short messages as ProgramChange (QMidiOut::setInstrument(int voice, int instr)) are then ignored when sending as qint32. Also with Midi Monitor these messages give an Invalid message after the intended message.

As solution I added QMidiOut::sendMsg16(qint16 msg) in QMidi_CoreMidi.cpp that has the same content as QMidiOut::sendMsg(qint32 msg) but sends only 2 bytes.