Add new drawables for download pause/resume

PS2:Whitespace

Change-Id: I9fb3b725fcac5f8fbc2f4316aca9188c5fda0814
SystemUI: prevent NPE on clear recents double press

Pressing Clear all button twice fast or while the list
is clearing but not yet fully cleared causes sysui to crash due to
mRecentTaskDescriptions being null: (http://pastebin.com/2gRFvf8k)

Workaround it by hiding clear all recents button.

Change-Id: I23d10edfd336041739fe80352ee01987e671dbd7
PB: enable MirrorMode and Reversed if activated