Blender Git Loki

Simple inclusion of alembic files from inside xml files for cycles
standalone.

The cycles XML files now can refer to Alembic (.abc) files. This will
call the default alembic reader to read in scene data. Currently it
simply prints the Alembic file structure.

Eventually a proper schema needs to be defined for both xml and abc.
Also care has to be taken to handle potential conflicts between settings
both within xml/abc and between them.