SlimActions: add new actions and cleanup

A bit cleanup.

As well add 4 actions:

- camera intent
- play/pause music
- next music track
- prev music track
- wake up device

As well check for system ready on the other audio actions which are already present.

ToDo: One of the rare classes which are very bad documented. We need to add code comments
ASAP

Change-Id: Ib327b39fbd709c6b77fca5febe97712348937c40