removed unneeded classes.
removed unneeded AST Closure to String class.
Remove a method from GraphProvider that is no longer needed for tests.
Remove todo - TinkerGraphProvider is being used everywhere.
Tested and tweaked Gremlin-Giraph via the console. Updated configuration parameters. Updated docs.
added LambdaHolder which greatly simplifies VertexProgram handling where lambdas are either objects, classes, or JSR223 scripts.