Revert "Settings: Reimplement PowerSaverManager !"

This reverts commit e0a6bc9303deb33630dd01ac4d7b0983f61d69aa.
Settings: Handle navbar heights correct on dpi changes + more (2/2)

Till now we set the height in px in the settings. Which is a problem
especially on multiDPI roms like we are when the user afterwards changes
the dpi due that it isn't calculated correct anymore on the new dpi.

This commit does
- save the dp value in provider and calculate the real px in fb
- clean up the settings stuff for it + do it a bit nicer (only settings part
  where we do not set the value for the listview)
- as well this commit disables movable navbar for tablets (we may will enable
  it in future but it needs a lot more work to have it on tablets correct working)
- add Converter class for common methods we always use....till now only px->dp
  and dp->px method

Change-Id: I1484f045ff80105c7bd70fe69ecd042fef42eec0
Settings: follow kitkat's ui

- manage apps; tab selector and ram usage
- battery data usage bar
- app widget toggle

Change-Id: I804b4b47563545d7ab124f4cc4800ef4034bf754