Created signals for event creation in BSONView

Event creation signal is sent in BSONView's POST handler and recived in Events.py.
After adding the new event to the creator's event list, I started to loop through to add event to all followers, but was advised against by Ceasar/Kyle. Here was code up to that point:
followers = db.users.find_one({'_id':u_id})['followers']
for follower in followers: ...

Also fixed the subscribing Mongo queries in Users.py.
Merge branch 'master' of https://github.com/pennappslabs/Events

Conflicts:
	app/views/events.py
	app/views/helpers.py
	app/views/users.py