Build on top of OWIN with Agent Routing

This is a shift in thinking from being buddy-buddy with Web API to simply using System.Net.Http types.

Benefits:
1. Can now deploy Client profile .NET 4.0 and probably as a portable library
2. Less Web API complexity
3. Get back to original ideas in Frank of using Rx/Agents

Cons:
1. Lose the Web API ecosystem
2. Must manually map to OWIN

To really work, this needs a type provider for the routing. However, I can implement a close approximation, which is in progress in this commit.

Note: not all the samples work.