Fix volume key music controls and wake up

- Forward port code from cm-11.0 and adjust for 5.0
- Fix not being able to adjust volume when music control is on
- Disable screen off volume/music control when wake key is enabled

Change-Id: Ie0ad83965c41fd33120490c25a4ff3d9b2cbeb37
Merge pull request #13 from CyanogenMod/cm-12.0

Fix volume key music controls and wake up