Blender Git Loki

Cycles: Add support for float4 textures on OpenCL.

Title says it all, this adds OpenCL float4 texture support.

There is a bug in the code still, I get a "Out of ressources error" on nvidia hardware here, not sure whats wrong yet.
Will investigate further, but maybe someone else has an idea. :)

Reviewers: #cycles, brecht

Subscribers: brecht, candreacchio

Differential Revision: https://developer.blender.org/D1983