Add user-generated annotations tests to the server (#1164)

* 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

server/test/test_anndata_adaptor.py

@@ -3,7 +3,7 @@ from os import path
 import pytest
 import time
 import unittest
-import decode_fbs
+import server.test.decode_fbs as decode_fbs
 from parameterized import parameterized_class
 
 import numpy as np