Updated MIDI CC handling not to count from 1 (#6774)

include/DataFile.h

@@ -127,6 +127,7 @@ private:
 	void upgrade_mixerRename();
 	void upgrade_bbTcoRename();
 	void upgrade_sampleAndHold();
+	void upgrade_midiCCIndexing();
 
 	// List of all upgrade methods
 	static const std::vector<UpgradeMethod> UPGRADE_METHODS;

include/MidiController.h

@@ -48,6 +48,7 @@ class MidiController : public Controller, public MidiEventProcessor
 {
 	Q_OBJECT
 public:
+	static constexpr int NONE = -1;
 	MidiController( Model * _parent );
 	~MidiController() override = default;