Pullrequests/data api

Use a message template instead of a plain message. If you use `logging.warn("notification exception: %s", e.message)`, then sentry can **group** all the notification exceptions together, instead of treating each one as a distinct event. The applies to all usage of logging; always use `logging.warn("var: %s", value)` instead of `logging.warn("var: %s" % value)`. See the bottom of this page: http://raven.readthedocs.org/en/latest/config/logging.html#usage