Mass refactoring

A lot of changes, a lot cleaner code.

A quick rundown:

- Converted `copy/` to Markdown (this will eventually need to be inserted into the site itself)
- Better comments (both inline, and PHPDoc)
- More and more tests - which is good, I think
- Refactored controllers, view helpers, forms, and Sass

(There should be minimal functional/stylistic changes introduced.)