Keyguard: repair/improve lockscreen blur with CM's theme engine

PS2: fix wallpaper flicker when exiting keyguard
PS3: fix problem with recycled bitmaps on devices with lower memory

Change-Id: I7509b74a20ad0a726bd5af63ad746936e77a1e69
Merge "Keyguard: repair/improve lockscreen blur with CM's theme engine" into kk44
fix hardcoded navbar spacing on tablets

Change-Id: I489ae1a1d675942e0756ff7073ab7eb0af4ea29c