Reworking, cleanup and documentation of `audio.Manager`
Added `options` attribute to 'Icecast' processor.

Moved `UnendingSource` from '__init__' to 'files' and renamed it to
`FileSource`. As it handles files, it should be in files.
Cleaned up audio.encoder and did documentation on the Encoder class.
Two small syntax errors fixed.
preparation on the restructure of the afkstreamer

Also removed a lone `print` statement in the `audio` package.
Merge pull request #61 from R-a-dio/upgrade1.3/streamer

Upgrade1.3/streamer (Generalization/Cleanup of `streamer.audio`)