fix for wrong diesel resolution

This PR resolves #207  Added two implicits to diesel, so Rdf#URI and Rdf#BNode should now be resolved out of the box.
All test pass. I also tried to make some some diesel code to see if there will be any name clashes but did not manage to find them.

> 1. it solves your problem and that 

It compiles. In some cases IDEA highlightning goes a little bit wild but as in the same time it compiles so I suppose it is IDEA's problem.

>2. you don't get divergent implicit resolution when passing an Rdf#Node.

You mean conflicting implicits? I tried  val alex: Rdf#Node = URI("http://bertails.org/#betehess") and  val alex: Rdf#URI = URI("http://bertails.org/#betehess")  and it compiled without problems. I undestand that for the same URI if it is represented as Rdf#URI another function will be executed but both implicit functions do the same job of creating a pointed graph.

P.S.: by the way, what does "W" mean in the end of classes and methods?