first take on neighborhood methods: OutEdges
fixed type info for the outEdgesFunction
use vertex/edge instead of tuples in the test
fixed a few warnings in pagerank example
some refactoring and cleanup
reduceOnEdges method for in-/out- and all edges
added simplified reduceOnEdges without the vertex value
Merge pull request #18 from vasia/neighbor-methods

neighborhood methods
SingleSourceShortestPaths example