Settings: Slimrecents background color && transparency [1/2]

Allow user to specify background color and transparency level
    for the slimrecents panel.

PS: now setting sticks through reboots and TRDS state
        changes. also, add reset to default color option.

PS: when resetting to default, use TRDS (png) resources
        instead of custom color

NOT USED FOR Liquid -> PS: properly set preference summary for default
        value ("TRDS default")

PS: remove LSN dependency

Conflicts:
	res/xml/recent_panel_settings.xml
	src/com/android/settings/liquid/RecentPanelSettings.java

Change-Id: I5c9fe11553bfce184e66b24ac76360e048bc7f0f