Added watermark functionality and unit tests
Added custom filter support
Allow to set bframe support in a format
Fix CS
Minor fixes
Merge branch 'letsface-feature/custom-filter'

* letsface-feature/custom-filter:
  Minor fixes
  Fix CS
  Allow to set bframe support in a format
  Added custom filter support
  Added watermark functionality and unit tests
  Fix Doc comment (width => integer)
  Add 'use FFMpeg\Coordinate\TimeCode;'