Commflag: Increase the value of MAX_BLANK_FRAMES.

For regions of blank frames between "skip" sections and "keep"
sections, the blank region is divided equally between the "skip" and
"keep" sections, subject to the MAX_BLANK_FRAMES limit.  The limit is
increased from 60 to 180 frames to give a better chance of an even
split, combined with a reasonable upper limit.

mythtv/programs/mythcommflag/CommDetectorBase.h

@@ -9,7 +9,7 @@ using namespace std;
 
 #include "programtypes.h"
 
-#define MAX_BLANK_FRAMES 60
+#define MAX_BLANK_FRAMES 180
 
 typedef enum commMapValues {
     MARK_START   = 0,