Added publishing functionality to Pubsubhubbub

Added the functionality of sending the alert to Pubsubhubbub.

Right now we have all the valid info only about pubsubhubbub . Will add a broker table later as and when more brokers are available.
Recall Dominic said: "alert_url = r.url(method="", representation="rss")" (only with cap not rss).
(Verify that the method is ok.)
And if you do that you don't need to import re.