Sybren A. Stüvel
084c5d6c7e
The goal of the `AbstractHierarchyIterator` class (and supporting classes) was to use it in different exporters. It shouldn't be part of the USD module + namespace any more, now that it will also be used in the upcoming Alembic exporter rewrite. The source files are moved into `io/common`, which is compiled & linked into a new library `bf_io_common`. The unittests are still inside the `tests/gtests/usd` directory. They should be moved to a separate test module too, but that will be delayed until after T73268 has been resolved. Reviewed By: mont29 Differential Revision: https://developer.blender.org/D7669