Before this patch, when recording Progressive (frame) mode, it recorded all
the frames correctly but set the clip's fps property to 25/29.97, so when
played back it played at half the speed (but was fine when played at double speed).
This patch does not affect the number of frames recorded per second, but rather
only sets the resulting clip fps property to the correct one (double than before).
Also fixes a bug that in a non-managed window in progressive mode, the title
displayed "200%" speed when it should have displayed 100% speed.
Fixes#832