Framecat

Fixed aspect ratio, improved logging, better variable typing

- fix mkdir issue if `~/Videos/framecat` does not exists

New features:
We move away from the frames -> GIF -> compressed GIF pipeline.
Now we can:
- generate GIF and compressed GIF from video
- generate compressed GIF from GIF
Tests are updated accordingly.
The README documents how to use these new pipelines.

Fix odd image size bug.

Initial version, published to PyPI.