Implement marshalling for exceptions.
This fixes a bug, where the Fake.Deploy.exe client would explode, if some exception was thrown in the agent.
Normalize Url before removing "fake/" from it.

This fixes a bug, where "http://127.0.0.1/fake" would not find a route, because of the missing "/" in the end.
Handle network exceptions.

Fixes a bug, where a network exception, e.g. 503 when calling http://127.0.0.1:8080/ would kill the client.
Listen on the root url, too.
This fixes the error, that the documentation claims, the url is http://mynode:8080, whereas before, it was necessary to use http://mynode:8080/fake/