Minor commit: Remove duplicate border-radius declaration on monitor-stream-image
Bug fix. Remove "haschosencameras" boolean.

* [0.7.72] - Remove duplicate border-radius declaration on monitor-
stream-image class
* [0.7.73] - Remove "haschosencameras" boolean and there's no need for
it anymore. Use chosencameras.length instead if needed. Added resetting
of frames array to clearPlayback() function.