Api Conventions

@the-hobbes, 

 Please note the addition of the conventions.md file in the api directory. Please review it and verify that these are indeed the convention's we are currently following. The spider is able to verify the comments endpoint, and the heatmap endpoints, by later tonight I am hoping to have it verifying the pins endpoint as well. The spider is being developed on it's own branch called feature/spider, however I have not pushed that to the remote repository. If you feel the desire to have the spider I will push it. Otherwise I'll keep it local until it's merged into the api branch itself in which case I'll submit another pull request to you so you can be updated.