Blender Git Loki

Fix for bug #3967.

It still needs some work but at least now it doesn't crash.

Basically it changed composit3_pixel_processor so that its using full
vector instead of first element (fac variable in the code).
In reality though its just pushing where its looking at the first element
of the vector to another function (do_mix_rgb)
which is calling ramp_blend with fac[0].

Kent