Updating PyCamp logo and links as per Chris Calloway's request.

Chris has asked for the links in the callout to PyCamp on the schedule
page to be updated to point to http://trizpug.org/boot-camp/torpy13/.

He also asked for a slightly different image to be used, to solve a
transparency problem (visible white square on the toe of the boot).

Fixes #91
Merge pull request #92 from felixc/update-pycamp-link-and-logo

Updating PyCamp logo and links as per Chris Calloway's request.
Lists the types of notifications a given proposal has recieved.
Provides /schedule/conference.json data feed to staff, for A/V. Fixes #78.
Removes Postgres-ism in the promoteproposals script.