Remove frameQueueSize setting.
Remove the toy "modern" graph.

Now that we don't have annotated lists/values anymore, the modern graph doesn't have much use.  All tests will work over gratefulgraph or the classic graph.
TODOs, notes, finalizing variables, this'ing stuff in MatchStep.
Add image to docs in gremlin server tuning section.
Merge remote-tracking branch 'origin/master'
Provide a legacy GraphSON reader to allow for migration from TP2 to TP3.
Graph.Variables now have get() Optional. and remove void. Added lots of JavaDoc to Graph.
EmptyProperty is now a singleton, no longer part of Property. Lots more JavaDoc on the main interfaces.
Traversal.Memory now returns Optional on get() and remove() is void. More test cases, more JavaDoc.
Add docs for "data migration" from TP2.
Merge remote-tracking branch 'origin/master'