Do not disable resize if source SAR != target SAR.
Remove audio/video composition; these effects are now merged with Audio/GL[Filter].
Introduce Transition. Transition stores one GLFilter and one AudioFilter.
Switch to QSharedPointer for sharing Filters.
Add an audio crossfade transition.
Add transitions.
Ignore more files.
Scene transitions handling.
Fix the case of consecutives transitions, where the movit chain is unchanged
but input frames have swapped:

      BBBBBBBB
AAAAAAAAAACCCCCCCCCCC

here, all inputs have the same fingerprint so the
chain is unchanged beetween A-B and C-B,
but in second transition B becomes the first input.
So, in case of duplicate (always true with images),
mmi is unchanged and input data not updated.
Introduce mmiProvider to fix this.
More transitions handling (resize and resizeStart).
Fix clip split to handle transitions.
Don't skip too much frames.
Display source file name before time.