"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/RecentsVerticalScrollView.java
Highlight the clear button in the recents view when clicked

This commit also makes copies of the ic_notify drawables for the recents
panel to avoid any collisions with possible future changes to the
notification bar UI. (The pressed state drawable was already an unused
leftover resource).

Change-Id: Ib0d5982e80771b6639efd25ac792ebfe9f1ca1c5
Recents : Fix clear all layout

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

Change-Id: Id43a3d0640f66c1d7c587cb272bc3a6ad520628b
am: Allow more hidden apps on devices with lots of RAM

 * If more than 1.5GB is present, allow up to 40 hidden apps.
 * Number is somewhat arbitrary, but was found to work well on D2.
 * Also look at the sys.mem.max_hidden_apps value if given.

Change-Id: I2d3cf6e0dad1bc0b482cc37bf9c61ed2f2b4be51