- changed MIDI sources so that they do not have to include i_musicinterns.h anymore.

They were already clean of unwanted external references, but including this file made it hard to keep it that way.
This also moves a few useful definitions around to less 'dirty' headers.

src/sound/midisources/midisource.cpp

@@ -34,7 +34,7 @@
  */
 
 
-#include "i_musicinterns.h"
+#include "midisource.h"
 
 
 char MIDI_EventLengths[7] = { 2, 2, 2, 2, 1, 1, 2 };