Hotseat: Allow customization of the app drawer button icon

Change-Id: Ic0904cafdd80c57851df9193eee6569cd4a2ae17
Hotseat: Add a check to make sure we're granted storage permission

Change-Id: Ib230256edf62cdfbc63bd33a6d24e45da1464d29
Merge remote-tracking branch 'omnirom/android-4.4' into Kitkat