GLMixer Code

Change order of logs testing: prevents processing app events before init
og glmixer instance.

Do not offer playback options for single frame media.

Improved manipulation of snapshot view (double clic enabled, zero
duration animation for direct restore of temp and destination snapshots)

oops: restore testing of depth boundary

Fixed behavior of snapshot interpolation in render view. Improved
behavior for setting depth in rendering manager.

Improved crop tool in geometry view: allow grabbing the whole texture
coordinates to shift texture inside source.

Updated behavior after QtFatal message to match new log management mode.

work in progress for a 1.8 splash

GUI cosmetics

Added preset Mask to show how to use a video as dynamic mask (using
lumakey)