Merged TypedDigraph into Digraph

Changed the Node Value Constructor to take a pair for it's payload,
where the first element (Int) represents the Node type.
Adapted to TypedDigraph/Digraph merge
Removed explicit TypeInfo from declarations

Adapted to new Node definition, where TypeInfo refers to all kind of
Nodes
Edge's payload now also has a type id
Adds Type Id's to Edges
Removed dependence on TypedDigraph.hs
adds edgeTypeCond

Adds new condition to check if edge types match
Adds edgeTypeCond test
adds edgeType function