Siti

* Fix behavior of -n option.

* Fix comment in release script.

* Note breaking changes.

* Update CHANGELOG format.

* Crop frame data to valid pixels to avoid edge effects.

* Add tests for sobel filtering.

* Add macOS hint for homebrew.

* Fix documentation.

* Remove unneded import.

* Fix tests.

* Update README.

* Merge pull request 5 from slhck/add-yuv.

add support for YUV

* Add support for YUV.

* Fix tests.

* Specify exact version reqs.

* Fix tests approximately.

* Fix setup script.