Finish update front end tests.
Reformat python code to conform to pep8.
Prevent error messages from pre-commit hook on OS X.
Merge db.collection.drop and pep8/frontend specs.
Merge pull request #159 from rcchan/client_collection_versioning

Add versioning to client session data
Be consistent about variable name shortening.
Merge pull request #158 from FuegoFro/master

Fill out front end specs for update and make python conform to pep8
Remove expired sessions
Session keepalive
Remove collections of expired sessions