REL: Release 0.5.3.

Apparently 0.5.2 already happened.

Author: Scott Sanderson

setup.py

@@ -23,7 +23,7 @@ def main():
 
     setup(
         name='pgcontents',
-        version='0.5.2',
+        version='0.5.3',
         description="A Postgres-backed ContentsManager for IPython/Jupyter.",
         long_description=long_description,
         author="Scott Sanderson",