Frameworks: remove always transparency mode navbar/statusbar 2/2

problem is that the transparency on most app totally break due
that a lot apps do not draw behind navbar and statusbar. Nearly
all user never use always mode and just use it on launcher
and lockcreen. So let us remove it
as well a bit cleanup

Change-Id: Ia5ee97f99102aa2b3833a33eb93b5e428a80b867
Frameworks: simplify custom lockscreen background code

- remove observer for transparency and handle it better
- add multisuser handles
- smaller fixes and code cleanup
- simpfliy custom background handling and change to our needs (thanks Danish)

Change-Id: Idf0bbb7bf9e132a3a68d567e3863cce1b6d99742
Merge "Frameworks: remove always transparency mode navbar/statusbar 2/2" into jb4.3
Frameworks: use a layer drawable for the keyguard

in preperation to the new navbar and statusbar transparency
managment which will come it is more consistent on custom image
and color fill on lockcreen to use a layerdrawable to add the
shadow on top of the image to keep on transparency of the background
the shadow like it is suggested by google

Change-Id: I22df7652b8be42cab1c9d1f0a13797da40a75dd9
Merge branch 'slim-4.3' into jb43