* Moved `mediagoblin.confirm` stuff to `mediagoblin.user_pages`,
templates too.
* Removed route extension for `mediagoblin.confirm`
* Created `delete_media_files` which deletes all media files
on the public_store when the entry is deleted
* Created a new decorator to check if a user has the permission
to delete an entry.
- overrides default tag parsing globals in test_mgoblin_app.ini
- piggybacks on existing test_submission code to check correct tag
parsing and storage in the database
- verifies expected behavior given different delimiters, case
sensitivities, tags that are too long, and extra whitespace
- verifies list-of-dict database storage and tag slugification
