Removed test videos from the repo. Refer to the README to learn how to acquire/recreate them.
Added SD video to gitignore
Bug Fix: Image sequences could get added to the processing list twice.
Bug Fix: getLength() counts frames if it can't read them from the header.
New: Added gifs to supported input files.
Merge branch 'develop'

* develop:
  Bug Fix: Image sequences could get added to the processing list twice. Bug Fix: getLength() counts frames if it can't read them from the header. New: Added gifs to supported input files.
  Added SD video to gitignore
  Removed test videos from the repo. Refer to the README to learn how to acquire/recreate them.