Revert "Give the drawer background more definition instead of just a solid color."

This reverts commit afa768b84c9a05f521a1efa6c3fdb5e8ce9d2157.
Revert "Introducing the PreferenceDrawerActivity which makes use of the new navigation drawer UI google has introduced in updates to many of their apps.  This relies on headers which are displayed in the drawer and preference fragments as the main content."

This reverts commit 3679a2ef220841fa4fd23c38eeef889a168ab354.