Settings: notification drawer background (1/2)

    so after keyguard is mostly done let us start notification drawer
    and QS. First one custom background.....either color or picture
    with custom alpha and ability to set a landscape picture seperatly
     if the user want. (lanscape phone only)

    Compared to the 4.3 included version completly recoded and better
    integrated. No idea what I thought 1 year ago on the old implementation

    cheeers

Change-Id: I23f4502e3d9e97f52245bbf3b41900939bb5c4ce

Conflicts:
	res/values/slim_arrays.xml
	res/values/slim_strings.xml
	res/xml/notification_drawer_settings.xml