0.9.2 released

Use docJGenerator 1.5.6.5 for the wiki generation
Support the "short", "cross", "convex", "crows_foot_one", and "skewed_dash" types for edges
Put some methods that were in the GraphMLDiagram class to the AbstractGraphMLDiagram class
Add methods in the GraphMLEdge class to directly customize the label position
Add methods in the GraphMLNode to directly add an edge from/to another node
Add a small application which allows to test the library using groovy