Hi, I needed access to the table and column management APIs, so I quickly added a few new methods to implement them. Not sure if the way I've implemented them fits the style of this library (untyped body: dict args, etc), but since you haven't added actual schemas for any of the other requests or responses I feel like it should be fine.

I also changed api.py a bit, to rely less on string concatenation and to use the urljoin function from urllib.parse (a python built-in) instead.