Refactoring of SherlockFragmentActivities in solo mode
FIX ClassCastException
FIX ClassCastException
Refactoring

Groups specific classes renamed with "Groups" prefix
New PlayerFragment superclass, aka UnisonPlayerFragment (not implemented for now)
FIX AndroidManifest
Clean up of the code

Removes unused imports, reformats some part of the code to satisfay checkstyle constraints.