add quicklinks in settings for novalauncher's settings and greenify's settings

:c

 Changes to be committed:
	new file:   res/drawable-hdpi/ic_settings_greenify.png
	new file:   res/drawable-hdpi/ic_settings_novalauncher.png
	new file:   res/drawable-mdpi/ic_settings_greenify.png
	new file:   res/drawable-mdpi/ic_settings_novalauncher.png
	new file:   res/drawable-xhdpi/ic_settings_greenify.png
	new file:   res/drawable-xhdpi/ic_settings_novalauncher.png
	modified:   res/values/strings.xml
	modified:   res/xml/settings_headers.xml
	modified:   src/com/android/settings/Settings.java