Added
* `compas_rhino.artists.ShapeArtist` as base artist for all shape artists.
* Added `layer`, `name`, `color` attributes to `compas_rhino.artists.PrimitiveArtist`.
* Added `layer`, `name` attributes to `compas_rhino.artists.ShapeArtist`.
* Added `layer`, `name` attributes to `compas_rhino.artists.MeshArtist`.
* Added `clear_layer` method to `compas_rhino.artists.PrimitiveArtist`.
* Added `clear_layer` method to `compas_rhino.artists.ShapeArtist`.
* Added `clear_layer` method to `compas_rhino.artists.MeshArtist`.
Changed
* Renamed `compas.utilities.maps.geometric_key2` to `geometric_key_xy`.
* Fixed bug in mirror functions.
* Fixed mirroring tests.
* Moved `BaseMesh`, `matrices`, `operations` to `compas.datastructures.mesh.core`.
* Added `transform` and `transformed` (and others) to `Mesh`.
Removed
* `compas_rhino.artists.BoxArtist`
* Removed `layer` attribute from `compas_rhino.artists.Artist`.
* Removed `clear_layer` method from `compas_rhino.artists.Artist`.