fb: fix on tablets notification drawer height on custom image background

The measurment bases always on the height of the complete view. Due that we set
an image as background (does not make a difference if we do it like now with an image
view or set the background resource for the complete view) the image is calculated into
the measured height as well which leads into the problem the the panel completly opens
to the bottom.

To prevent that measure only the real content and decide based of this value how much the
rubberbands should go into action. This will be only done on devices which set a minimum
height for the drawer which indicates that we need to measure the content more exactly.

Change-Id: I9772abc8a48d5e46b5bb6e6239c0b4826115ac6a

Patchset: 3
https://gerrit.slimroms.net/#/c/3096/
fb: restore navbar compatibility with several xposed modules

I am tired of the complains....

Xposed use the emulator overwrite to enable/disable navbar...this results
into showing up navbar on reboot even if the user has set it to off in settings.

This fixes the issue and still keeps for emulator tests the basic overwrite functionallity
alive as long the provider value was not set.

We may should reflect that in settings as well.

Change-Id: Id60b45645d489c08539d56b8e05d135c36d38990

Patchset: 4
https://gerrit.slimroms.net/#/c/3098/