Blender Git Loki

Compositor: Add vars and methods for easier image looping

These variables and methods should make it easier to loop through buffers elements/pixels. They take into account single element buffers.
Single element buffers can be used for set operations to reduce memory usage.

Usage example: P2078

Reviewed By: #compositing, jbakker

Differential Revision: https://developer.blender.org/D11015