New papers column on homepage is generated from db
All homepage columns are now generated from db
Added testcases
Added @classmethod to static methods
Implemented more efficient version of trending()
Simplified trending() code.
Use count() in num_reviews() to prevent fetching all reviews.
trending() promises to return a list, which it didn't. Fixed.
Merge branch 'master' into issue-5

Conflicts:
	openreview/apps/main/tests/paper.py
	openreview/apps/main/views.py
Merge pull request #11 from martijnbastiaan/issue-5

Issue 5