Move vendored libraries to vendor directory

vendor/sqlalchemy/testing/mock.py

@@ -0,0 +1,15 @@
+"""Import stub for mock library.
+"""
+from __future__ import absolute_import
+from ..util import py33
+
+if py33:
+    from unittest.mock import MagicMock, Mock, call
+else:
+    try:
+        from mock import MagicMock, Mock, call
+    except ImportError:
+        raise ImportError(
+                "SQLAlchemy's test suite requires the "
+                "'mock' library as of 0.8.2.")
+