[c] Fixed leak in AnimationState, wasn't disposing mixing from entries when entire state is disposed. Confirmed that disposing of mixing froms is done properly if anim state is allowed to update until the mixing from is done.

spine-c/src/spine/AnimationState.c

@@ -175,7 +175,8 @@ void _spEventQueue_drain (_spEventQueue* self) {
 }
 
 void _spAnimationState_disposeTrackEntry (spTrackEntry* entry) {
-    FREE(entry->timelinesFirst);
+	if (entry->mixingFrom) _spAnimationState_disposeTrackEntry(entry->mixingFrom);
+	FREE(entry->timelinesFirst);
 	FREE(entry->timelinesRotation);
 	FREE(entry);
 }