* Add undo/redo tests for annotations
Fixes https://github.com/chanzuckerberg/cellxgene/issues/969
... also refactor the tests for DRY.
* Add done()
* Make e2e annotations tests safer to concurrency
* Add data-testclass for save state.
* Simplify tests and make them dependent on save state
* Add user-generated annotations tests to the server
Partially completes https://github.com/chanzuckerberg/cellxgene/issues/969
* Auto-format python code
* @skip_if: passing lambdas > than property strings
* Respond to feedback from @bkmartinjr
