Started on ambient occlusion shader.
Merge branch 'master' of https://github.com/worklist/hifi into ssao
Started on C++ side of SSAO effect.
Merge branch 'master' of https://github.com/worklist/hifi into ssao

Conflicts:
	interface/src/Application.h
Missed a spot in the merge.
Remove the code here; will be replacing it based on glow effect work.
Merge branch 'master' of https://github.com/worklist/hifi into ssao
Beginnings of ambient occlusion.  Looks like an architectural drawing.
Merge branch 'master' of https://github.com/worklist/hifi into ssao
Basic ambient occlusion effect up and running; needs tweaking and
optimization.
Square vector lengths to bunch them up towards the center, add a minimum
length, include the URL of the SSAO tutorial.
Merge branch 'master' of https://github.com/worklist/hifi into ssao

Conflicts:
	interface/src/Application.h
Merge branch 'master' of https://github.com/worklist/hifi into ssao
Merge branch 'master' of https://github.com/worklist/hifi into ssao
Added toggle for ambient occlusion (defaults to off).
Merge pull request #865 from ey6es/ssao

Basic screen space ambient occlusion effect.  Defaults to off, because at the moment it slows things down substantially.