Allow disabling non intrusive incall ui
https://github.com/omnirom/android_packages_services_Telephony/commit/171680ae4608f1d3ebbb5fb615b30ef33f1e4816

Conflicts:
	res/values/purity_strings.xml
	res/xml/call_feature_setting.xml
	src/com/android/phone/CallFeaturesSetting.java