Revert "Add an option to enable/disable the Navigation Bar (2/2)"

This reverts commit 6540b6b119cdbc9b322acc11f7ef622a95d0ebfd.

Conflicts:
	res/values/pa_strings.xml
	res/xml/more_device_settings.xml
	src/com/android/settings/cyanogenmod/MoreDeviceSettings.java