Fix small issue found in vertex color bake bug that caused the result to be
different each time, due to float precision issues. The camera matrix itself
should not be modified in render, just its copy.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54040 954f8c5b-7b00-dc11-b283-0030488c597c
Code cleanup: move render baking code into own file.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54041 954f8c5b-7b00-dc11-b283-0030488c597c
Fix #33905: cycles crash with bsdf node plugged twice into add shader.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54042 954f8c5b-7b00-dc11-b283-0030488c597c