moved global variable "pc" to player.h

This is the last of the three variables.  Now we don't need
playerData.h anymore in most sources.

src/decoder_list.c

@@ -18,6 +18,7 @@
 
 #include "decoder_list.h"
 #include "decoder_api.h"
+#include "list.h"
 
 extern struct decoder_plugin mp3Plugin;
 extern struct decoder_plugin oggvorbisPlugin;