"Clear all" button on recent apps

    Ported from ParanoidAndroid by zigackly:
    https://github.com/ParanoidAndroid/android_frameworks_base/commit/f8c44e6ef667a3ebe9b658f148fa78a8d4f9a8dd

    Add button to tablet layout ported from Codename Android by zigackly:
    https://github.com/CNA/android_frameworks_base/commit/8d259fe3588c261baa5a17c361255cf28cc82bfe

    Patch set 2: Make the layout consistent, with the button at the top right.

    Patch set 3: Remove the redundant use of removeTask()

    Patch set 4: Top right layout does not work in tablet mode: make it top left for tablets only.

    Patch set 5: Different implementation (No need to keep track of views) - Danesh M

    Patch set 6: Top left layout no longer works for tablet mode with new implementation.
                 Make it bottom left for tablets only.

Change-Id: Iceb86eef41160f1c17e51463b37fd97e27acfb2e

Conflicts:
	packages/SystemUI/res/layout-port/status_bar_recent_panel.xml
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java

Change-Id: I5f3827299866a951e657ce64bea7c5f31c34ef9e

Conflicts:
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java

Conflicts:

	packages/SystemUI/res/layout/system_bar_recent_panel.xml
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java
Recents : Fix clear all layout

Fixes the clear button from getting cut off due to the added
fitsSystemWindows in aosp

Change-Id: Id43a3d0640f66c1d7c587cb272bc3a6ad520628b
TODO: Show "Clear all" button only if the navbar height is 0

Uncomment when its ready!

Change-Id: I23efca306b97ebf3835223b3b3a5db6d44306df2
SystemUI: Fix missing top task in recent panel.

If preloadRecentTasksList was not called or was called too
late and RecentsActivty already started and last top activity has
excludeFromRecents flag setted it might be missing
from recent application list.

Change-Id: Idf7153824805ceea9fcaf04ac645b73a5e93a4d9