On the go mode squashed

originally from Nameless ROM Author: Evisceration <eviscerationls@gmail.com>
ported to be compatible with vanir with minor improvements

On-The-Go turns on the camera of your phone and streams it to an overlay, which
is drawn over everything. this makes you feel like your display is transparent,
as you see the content behind it.

squash of additional improvement commits:
 http://gerrit.nameless-rom.org/#/c/3593/
 http://gerrit.nameless-rom.org/#/c/3594/
 http://gerrit.nameless-rom.org/#/c/3595/
 http://gerrit.nameless-rom.org/#/c/3724/
 http://gerrit.nameless-rom.org/#/c/3733/5

Change-Id: Ic0c2fdff0bd7789f55135c288452874e74cc5de3