Custom lockscreen wallpaper [1/2]

Conflicts:

	packages/Keyguard/src/com/android/keyguard/KeyguardViewManager.java
	packages/Keyguard/src/com/android/keyguard/KeyguardViewMediator.java
	policy/src/com/android/internal/policy/impl/keyguard/KeyguardServiceWrapper.java

Change-Id: I6b0cd091f5d3c14d267921c047f0308929fe7cf2

Custom Wallpaper: use PNG and fix derp

This should fix the bad lockscreen wallpaper quality after reboot.

Change-Id: Iff461b109f79cf99fa99a7ab89ad57864c8a0dbc