Blender Git Loki

Alembic: export object data with object data name

Previously the Alembic exporter exported a mesh object to
`{object.name}/{object.name}Shape`. Now it exports to
`{object.name}/{mesh.name}` instead. The same change also applies to
other object data types.

Note that the code now is a bit hackish, as `m_name` is set even in
cases where it isn't used. This hackishness was already there, though,
but it's now just more visible. This will all be cleaned up when the
Alembic exporter is ported to use the `AbstractHierarchyImporter`
structure of the Universal Scene Description (USD) exporter.

Reviewed By: mont29

Differential Revision: https://developer.blender.org/D7672