Add "Environment" class for configuring the breadcrumbs

[justintadlock]

There are many ways that the various classes can be extended or overwritten on the PHP end. However, they are still a bit clunky. In fact, I removed a few filter hooks for version 1.0 to deter others from extending them in one way.

Ideally, we'd have an Environment class for configuring which Query, Build, and Crumb classes are used. Filters could even be run at this point for easy extension. Overall, the goal would be to make it easier for build on top of the system for more complex plugins with unique URL structures by just passing in a set of custom classes.

This is probably not explained well here in this ticket, but some preliminary stuff exists for this in my head and a local notes file.