* support other popular codecs
* use install_ffmpeg.sh from go-livepeer, refactor tests
* set environment variable to build ffmpeg with tools and modules required for tests
* Fix NV-SW encoder selection
* Change HEVC display name to be alphanumeric
* refactor tests
* refactor tests
* refactor tests
* Fix unsupported codec test comments
* Bump to trigger CI
* Set env for dynamic libraries
* Test cleanup, temporary use install_ffmpeg.sh from go-livepeer branch
* Create cache key with right install_ffmpeg.sh
* Bump to trigger CI
* Switch back to master install_ffmpeg.sh
Updates the API to the changes introduced in 129d5b2b9.
Also fix CircleCI, because `go get` attempts to build the example
from a (broken) master branch by default even though we really want
$CIRCLE_BRANCH.