Dynamically generate request methods

[ErikBoesen]

One big issue with how I designed this package initially is that I hardcoded every method, even though there were clear patterns, for example many methods were repeated several times for different domains, and each endpoint often had to support several HTTP verbs (GET, POST, etc). It would be nice to do some fancy Pythonic code-generation so they wouldn't all be hardcoded.

That said, I'd prefer to entirely restructure the way requests are built so we don't have one big class with all the methods, as explained in #14.