The ClayEngine was introduced to test the blender2.8 architecture during
development. As currently we have the wanted features implemented with
matcaps we are going to remove the clay engine as it was never intended
to be an official releasable engine
Note: The test cases are never run. But when enabled will be skipped as
they were implemented over the Clay Engine
The RenderResult struct still has a listbase of RenderLayer, but that's ok
since this is strictly for rendering.
* Subversion bump (to 2.80.2)
* DNA low level doversion (renames) - only for .blend created since 2.80 started
Note: We can't use DNA_struct_elem_find or get file version in init_structDNA,
so we are manually iterating over the array of the SDNA elements instead.
Note 2: This doversion change with renames can be reverted in a few months. But
so far it's required for 2.8 files created between October 2016 and now.
Reviewers: campbellbarton, sergey
Differential Revision: https://developer.blender.org/D2927
