Ability to support different attributes for routing.

Being able to support other attributes for the routing I can see being potentially valuable for sharing of an interface on the client and server. Worked with this a bit and reading issue #6.

I have created this pull request to show my current thinking and get some feedback if I am on the right track with this. I have had a bit of a look at the IContractResolver mentioned by @jamesnk and gave this a shot.

Some of the things I am just wondering about:
* Naming - Is RestMethodResolver appropriate (Naming is hard :tm:)
* Is there anything I should watch out for being portable?
* Should `GetInterfaceRestMethodInfo` have the interface type passed as the parameter or instead the individual MethodInfo objects? (More I think about it leaning towards passing the MethodInfo objects.
* How should the files should be split out what approach would you like taken? For now they are just bundled into one.

Any other thoughts on the approach?