SlimRecents: add floating window menu

-Rename the string it uses because we already have one for notification long-press
-Delete all transparent stuff, we do not use it

Change-Id: I63894fb8551b881c45c991bc30353b3dc4f3e43c

Conflicts:

	packages/SystemUI/src/com/android/systemui/slimrecent/RecentPanelView.java
Fix Slims recents floating mode

Took the idea from here: http://goo.gl/msdLYv

Change-Id: If0ec2f627b4abd9aec4fd13f7e289319d72e9146