Fix use of deprecated NSDocumentController API that the compiler didn't warn me about.
Fix use of deprecated NSDocumentController API that the compiler didn't warn me about.

DouglasHeriot/MIDIApps,krevis/MIDIApps,krevis/MIDIApps,krevis/MIDIApps,DouglasHeriot/MIDIApps,krevis/MIDIApps,krevis/MIDIApps,DouglasHeriot/MIDIApps