Rework internal module registration to happen in constructors.

src/modules/audio/Audio.h

@@ -101,9 +101,6 @@ public:
 
 	virtual ~Audio() {}
 
-	// Implements Module.
-	virtual ModuleType getModuleType() const { return M_AUDIO; }
-
 	virtual Source *newSource(love::sound::Decoder *decoder) = 0;
 	virtual Source *newSource(love::sound::SoundData *soundData) = 0;
 	virtual Source *newSource(int sampleRate, int bitDepth, int channels, int buffers) = 0;
@@ -312,6 +309,10 @@ public:
 	 */
 	virtual void setPlaybackDevice(const char *name);
 
+protected:
+
+	Audio(const char *name);
+
 private:
 
 	static StringMap<DistanceModel, DISTANCE_MAX_ENUM>::Entry distanceModelEntries[];