Forward port "Display options: allow configuration of wake on plug behavior"

From http://review.cyanogenmod.org/#/c/47159/

Change-Id: If1d50cbad76763bb8e12b2e7a4f7c21f42a58f31

Conflicts:
	res/values/cm_strings.xml
	res/xml/display_settings.xml
	src/com/android/settings/DisplaySettings.java