Forward port Status Bar settings

Patch Set 2: Rebase
Patch Set 3: Commit message
Patch Set 4: Remove (default) designation in AM/PM style options
Patch Set 5: Remove Combined Bar options
Patch Set 6: Remove Auto Brightness Slider options
Patch Set 7: Adjust Signal status style availability according to new tablet devices
Patch Set 8: Rebase
Patch Set 9: Updated commit message

Change-Id: I1632b6454a3fd5240179dfed34b1f332a7a37cda

Conflicts:
	res/values/arrays.xml
	res/values/strings.xml
Status bar brightness control from CM10 (2/2)

Change-Id: I0b2765e0d66c9ac4f205d47677422bd86c7f49ba
Hide the AM/PM preference completely if using a 24-hour clock

In addition, this commit also fixes a bug where the switch would not be
disabled on a fresh 24-hour clock install, as the preference value would
be null. This is avoided by using a higher-level method from
DateFormat to check the clock mode.

Patch Set 2: improve code styling

Patch Set 3: remove pointless application context retrieval

Change-Id: I80de938df61803649688723843439905e9909b07