flake8 fixes for the schedule edit form. imports were missing. added a TODO for the atomic call, which is not supported in django 1.4
Merge pull request #63 from codersquid/flake8scheduleform

flake8 fixes for the schedule edit form.
Adds a schedule_json view which provides a /schedule/conference.json endpoint, of the kind that Carl uses for producing conference videos.

Also useful to feed into mobile schedule apps!

It is expected that someone might have to customize this for their own installation (PyCon Canada definitely did, with modifications to some of the models).
adds a schedule json endpoint. based on @taavi's PR #45 with some changes from the @pyohio/pyohio repo
flake8 fixes
added cancelled element to json, used taavis start/end props
flake8 fix