[MacOSX] When running from command line in batch mode, switches screen away from terminal

On OS X, invoke MuseScore (mscore.app/Contents/MacOS/mscore) from the command line with the batch mode -o parameter. The screen will be switched away from the command line as if a new GUI window is going to be created.

This is a nuisance for scripts that use MuseScore in batch mode on a large number of files.