Merge pull request gopro#169 from ucabvas/patch-1

Fix demo

demo/GPMF_demo.c

@@ -82,7 +82,7 @@ int main(int argc, char* argv[])
 		return -1;
 	}
 
-#if 0 // Search for GPMF Track
+#if 1 // Search for GPMF Track
 	size_t mp4handle = OpenMP4Source(argv[1], MOV_GPMF_TRAK_TYPE, MOV_GPMF_TRAK_SUBTYPE, 0);
 #else // look for a global GPMF payload in the moov header, within 'udta'
 	size_t mp4handle = OpenMP4SourceUDTA(argv[1], 0);  //Search for GPMF payload with MP4's udta