SystemUI: Always show translucent decor on recents panel

Change-Id: Id3e371f841b065ba6ac7693d96b38504354b4fd9
Fix hot reboot in powermenu

Fixes AOSPA-557
Accessing showGlobalActionsDialog() from different threads
(one for broadcasts and one for the actual longpress power button action)
caused a hot reboot when accessing the power menu from quick settings and then from power button.

Change-Id: I4b6efd192404f073c0d1b5655152ae736a398cbd
Pie: Fix navigation icon hints being cleared on reorientation

There is no reason to recreate the PieControlPanel instance if it already exists.

Change-Id: Id7bb4946a8fbd4595e840c605b90b97cab7b38ca
Implement DocumentsProvider.createDocument and deleteDocument

Fixes AOSPA-431
This is needed to delete and create files/folders in DocumentsUI.
Some open questions are:
1. Are the methods implementented according to their description?
E.g I'm not sure whether deleteDocument should be able to delete folders, too.
2. I first didn't want to modify public API, but deleting files from within DocumentsUI somehow doesn't work - file.canWrite() always returns false
3. So is modfying the API this way OK?

Change-Id: Ie3a9d1888decaa0f08de1a5183ffd23760be15b9
Pie: Fix Pie positioning when PIE_ALWAYS_AT_RIGHT

Locking Pie to a single physical side of the screen makes perfect
sense when it's done on the short side of the screen (bottom in
portrait) as then Pie is more easily swipeable in at all times, but
a user might instead prefer being able to quickly swipe in from the
right or left hand side in portrait which becomes cumbersome when the
device is turned to landscape as the user is then forced to reach to
the middle of the long side of the screen which becomes located at
the bottom making it harder to access Pie.

The PIE_ALWAYS_AT_RIGHT value should be used to solve this issue
by forcing Pie to relocate itself to the right hand side just
like with the stock navigation bar.

Change-Id: I9b4dd3cee3fa7d85194389640dcedc02fa522530