Set up a default cookie key name of "mongo-express" to prevent it from overwriting cookies for other express apps using the default cookie name.
Moved the cookie key name into the config to make it more obvious that it's something that can be customized.
Enable search by ObjectID.  TODO: validation to prevent errors with invalid objectID
Updated ObjectID search to allow for multiple formats and turned on basic validation to prevent crashes.  Error message is flashed to the user.
Merge pull request #22 from marshallswain/master

Added search by ObjectID and Set up a distinct cookie key name.