When open QS wifi panel while wifi was off was causing a crash from
wifi enabling while the WifiTracker was not in a scanning state.
Fix plus a test enclosed.
Bug: 19322090
Change-Id: Id863cdcbf4aa8d50822de3a200355dbaee74b488
Make SettingsLib capable of tracking which wifi networks are
available/saved and their state.
Also modify Quick Settings to use this code rather than having
its own logic.
Bug: 19180466
Change-Id: Iff9f9aed240d79323dba41496496e8076b9fa6f2