General Post API bugfixes

[mcavoyk]

Some general issues with the post API:

• When a user gets a post, voteScore should be set based on their previous vote action
• When a post is created, the creator of the post should automatically upvote it
• Posts should be ordered by some combination of score/time since post creation
  • Was thinking something like (wilsonScore * (.99995^seconds since posting))
  • Will need to keep track of upvotes/downvotes separately