Get ready for drink/config system refactor

The drink system has finally been thought out. This branch was used to test some ideas, and can now be merged.

The plans for the drink system are:

- YAML-based configurations with embeddable Python via *Jinja2* (much like *Ansible*'s system)
- Cleaner system for user-built drinks with a better base class
- Use *Bunch* for better configuration dictionaries loaded from YAML