New API Design

[JMurph2015]

So the API is pretty garbage right now. Lets figure out how to fix it.

Vision

Currently I envision a (mostly) two struct system, a Controller and a Channel, a lot like the @meh implementation from a while back, however, there are some improvements to be made there.

General usage flow

1. Get a mutable reference to a Channel from the Controller, perhaps via the indexing traits
2. Index on that Channel using some higher level color type and set desired color values for the LEDs
3. Call controller.render() when finished with this frame's changes

It's not all that different from the C API, but hopefully we can integrate some of those zero cost abstractions that everyone loves, especially around the color typing and the error handling. Realistically, we're going to have to get creative if we want to store richer color types co-locally with the actual 0-255 byte representation in the driver. I'm not even sure its worth messing with in this low level of a library.

Anyway, feedback is greatly appreciated!