add scenegrapherror handler, unused right now
switch from doing an fbo copy of the game scene, to doing inline rendering

means we just got rid of an extra fbo blit, and storage..saved ~15mb
of vram, at rough benchmark. everything is back to normal except
the fullscreen escape menu effects, which i'm not sure how to do at this
time.
fully remove fboinsgrenderer, huge performance win here

before:
https://i.imgur.com/xeXNE0u.png

aka using the "game scene is a texture node that QQ renders on its own"

after: https://i.imgur.com/O5ILgeR.png

by rendering directly with beforerendering.

on this mesa 10.2.5, that is a huge difference (48fps -> 60fps), huge
buffer wait time decrease...and other things, like -7mb or so of vram
(on this 1366x768 laptop). hw is amd 4250 HD (old and crappy, but 3.3
capable).
reinstate some kind of escapemenu backgruond thing (rect for now)

means we commented out the various shader effects..may have to do those
manually sometime.
Merge branch 'master' into add-z-pos

Conflicts:
	src/client/FboInSGRenderer.h
	src/client/camera.cpp