templates: add status_code and checked in list of memes
improve error handling in reldatetime filter
implement celery for task queueing
fix bug where whooshalchemy didn't like blank fields
make Meme model use UnicodeText
make scraper.crawl actually work!
turn on celery processing for memes in development server
return index_service from models.setup()
add celeryd and set it up in fabfile
add status filter for http statuses, add checked status to meme.html