Added margin to top of page (for nav bar)
Added comment template
Refactored article list/display to use objects
Merge pull request #9 from joe752/master

Comments have Articles as Parents
Merged Joe's comments updates.
Updated comments data storage
Added comments index
Extracted html from comment.py
Fixed time_since to handle singular units
Added Hacker News-inspired ranking algorithm
Added login redirect on vote
Shrank article poster and time
Added js url validation to post_article page
Removed redundant comments entry
Fixed error with comment sorting
Added z-index to nav, so it will always be on top
Attempting to comment when not logged in will not cause error