This release should work with FFmpeg 2.0 and Libav 9.8. It probably also works with FFmpeg 1.2, 1.1 and (if libavresample is enabled) FFmpeg 1.0. git version of FFmpeg and Libav work too, however it could be that later git versions of them introduce breaking API changes.
There is nothing special about this release. We just thought it was about time to start making releases, and git master seems to be relatively stable currently.
If there are bugs to fix, a branch named "release_0.1" will be created. The branch will contain fixes cherry-picked from master. Fixed versions will be released as v0.1.1, v0.1.2, etc.
Once v0.2.0 is released, support for v0.1.x will be dropped. Major releases will probably be made every 2 months.
Once the [milestone 1](https://github.com/mpv-player/mpv/issues?milestone=1&state=open) is completed, v1 will be released. This might happen before v0.2 is actually released.