[WIP] Updated plug. Refactor Router/Controller.

Fixes #54.

First part of a major refactor in order to allow Sugar to track Plug's latest versions easier. Leveraging the Placid way of handling Routers and Handlers (Controllers) so that they are more Plug-oriented and can use plugs in a more idiomatic way.

Remaining bits include ensuring older functionality continues (even if under a different name), including hooks and filters (which both should be good to go with the internal Plug stacks brought over from Placid's implementations).

When complete, this should easily pave the way for the completion of #16, #17, #41, and #55.

Comments welcome and encouraged.