Notification drawer custom background + notification rows transparency (2/2)

Change-Id: I46b09a82f1a5c6dbd0b9fcb812fa2461d66f5e2c
Colorpicker & SeekBarPreference.java

Change-Id: Ic365ef4af6fa31eed0afbf0a732e71086d746e20

Conflicts:
	res/values/pa_strings.xml