Add support for CMHome (1/2)

Add permission for DashClock extensions.
Change Trebuchet to allow viewing additional screen.
Add setting that to configure Google Now / CMHome.

Change-Id: I63286a2cce87455ed411bd4c77680200eec89be7
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0

Conflicts:
	res/values/preferences_defaults.xml