Ignore some maven temporary files which are part of releasing
Remove merge fail stuff
Extra ignore from extra file turded into install dir
Post processing task to generate stuff not done by maven
[maven-release-plugin] prepare release 1.7.5
[maven-release-plugin] prepare for next development iteration
[maven-release-plugin] rollback the release of 1.7.5
change vertexFor to findOrCreateVertexFor

- vertexFor method has a side effect of creating new vertex if there
  is no vertex with given data
- findOrCreateVertexFor explains this intent more clearly