Fixes Audio/Video Sync Issue

Based on the comment on an issue: 
 (Quote)"jallens commented 4 days ago
i fix it.

in file : CSScreenRecorder.m line : 516
add:
[compositionVideoTrack scaleTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) toDuration:audioAsset.duration]; " (End Quote)

This was tested and successful by nicolasgomollon on his version of RecordMyScreen! (RecordScreen)