Default to diffuse/add mode, fix for interacting with ambient occlusion.
Unfortunately, I managed to break the diffusion somehow.
Merge branch 'master' of https://github.com/worklist/hifi
Turns out we do have to initialize the "odd frame" field.
Fewer texture lookups when diffusing.
Might as well convert the divide to a multiply.
No glow effect on the avatar, fixed OS X warning.
Merge pull request #875 from ey6es/master

Fix for diffuse glow with SSAO, made diffuse glow the default, improved performance, added debug statements.