drawable-sw720dp: Update workspace screen background drawables

Change-Id: I326c3922c7de6280f0d0fc28d3bf387407d11e3c
Workspace/AppsCustomizePagedView: Improved transition effect dialog

Change-Id: I7c611ee9702c3a5b945644721948c4724f7639a7
trebuchet: Fix shortcut install/uninstall permission name

AOSP 4.4 has a public INSTALL_SHORTCUT/UNINSTALL_SHORTCUT permission.

Change-Id: I11cf09b4964838b2366ec37646392ff61be6c529
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>