Bufferer

* Bump version.

* Print commands in dry run such that they can be copy-pasted into shell.

* Bump version.

* Add re-encoding to force fps when muxing.

* Add pypi badge.

* Format README with preview file.

* Bump version.

* Reintroduce format strings for Python 3.5 compatibility.

* Bump version.

* Separate processing of audio-video.

- Process audio and video separately to ensure that everything is synchronous
- Remove Python 2.x support; require Python 3.6+

* Implement new changelog through gitchangelog.

* Bump version.

* Fix handling of labels.

* Bump version.

* Bump version.

* Set rate for black filter.