Settings: Hide Development settings when it is turned off

This commit hides the Development and Performance settings items
when the user turns off Development settings. This sets things back
to tapping x number of times on the build number to once again enable
developer settings

Patch set 1,2 : Initial commit
Patch set 3   : Fix case where, if user toggles off and on without
                exiting Development settings, the main menu items
                should remain visible
Patch set 4   : Fix typo in comment

Change-Id: I6003f73f5abee54bb000f01757ecffe7b68dba59