NavigationBar: Custom height (2/2)

Ported from http://review.cyanogenmod.org/#/c/23610/

Change-Id: I751ae54de1adf96367948735558363ce0dbb9f89

Conflicts:
	res/values/arrays.xml
	res/values/strings.xml
	res/xml/system_settings.xml
	src/com/android/settings/cyanogenmod/SystemSettings.java

Conflicts:

	res/xml/system_settings.xml
	src/com/android/settings/cyanogenmod/SystemSettings.java