Revert "SystemUI: change back button to hide ime buttom with rotate animation."

This reverts commit a865582ef4946c066952920a341e085304113bb0.
Clear Recent Apps (From NavBar)

Original author: TheMrcool212

this is not using cm's clear recents way, cm uses a button to clear recents but mrcool coded like pa's way at kk based pa roms so navbar recents button turns to clear all button when you open recents menu.
Don't remove the last app
pm: Add persist property to enable lazy dexopt

 * Add "persist.sys.lazy.dexopt" property to enable lazy dexopt
   on userdebug builds.  As much as I enjoy these 20 minute
   dexopt sessions, I prefer instant gratification.

Change-Id: I568692f04d67c3c0a1a138fb724eda41e24b1235