Relationship resolver

It would be nice from a UI to have access to all the mods which are in conflict and not pull out a single pair from a exception string.
While there I rewrote some parts. 
Ah! When we're getting the results back from a `new` call, we're happy with var (since the type is obvious), but for regular calls we've been trying to put it in. Especially for me it's been tremendously useful to know what type everything is, especially because our code uses a mixture of identifiers (strings) and `CkanModule` types when dealing with modules themselves.