TINKERPOP-1872 Apply edgeFunction in SparkMessenger

[Stargazer4869]

Re-create the pull request to replace the one on master branch.
The edgeFunction defined in Local MessageScope will not be applied anywhere when you are using SparkGraphComputer. It will cause a difference in result with what you will have when you are using TinkerGraphComputer.

[spmallette]

sorry, it too me a while to get to this. It looks like you have a good unit tests for SparkMessenger but is there an integration test that would also work so that it could be added to the general test suite. In this way we could see it executed against TinkerMessenger and potentially other places where an edgeFunction might be in use?

[Stargazer4869]

Hi, @spmallette
Is there an integration test case which involved TinkerMessenger or TinkerGraphComputer? I could write a similar one for SparkGraphComputer. It will make it easier for me to create an integration test case for SparkMessenger

[spmallette]

Please see #793 which contains your changes here plus an integration test i was able to write to produce the problem. I wasn't sure how to advise you to do it, without doing it myself, so I hope you don't mind my finishing this one up for you. Please close this pull request when you get a moment...thanks.