MacGui: Maintain Picture Filters state across sources

MacGui: Maintain Picture Filters state across sources
- Picture filters no longer reset to their defaults when a new source is chosen (includes vfr as well setEnabled to the fps drop down in the main window).
- Added a new method -setInitialPictureFilters to PictureController.m to setup the filters upon first scan instead of in -SetTitle which reset them every time a new title was accessed.

git-svn-id: svn://localhost/HandBrake/trunk@1148 b64f7644-9d1e-0410-96f1-a4d463321fa5