Trivial update to table header in API.md
Created by: jnmclarty
This PR just makes the titles of all the table headers match exactly.
Why do I care?
Assuming you merge this, I can use one line of python to build a python-wrapper for your API, using code-generation off of the markdown. My code works now, pointed to my own branch, but if you guys keep this file consistent, my python wrapper can be tightly-coupled to your routes, and super light-weight for a human to maintain.
Ill share the python wrapper ASAP.