Add regex support for URI matching

[BenjamenMeyer]

Present support for URIs is basically strict text match - x == y. To be really useful there should be some kind of ability to match based on regex patterns - x.matches(y).

[BenjamenMeyer]

Let's prove the current functionality is fully working, fully test covered, etc before this is added. May be a 0.1.1 issue as it would probably be good to have it in before the documentation gets fully written...not sure.