TraverserSource is simply a marker interface now -- no methods. Internal to StartStep (thus, GraphStep, TinkerGraphStep, etc.), there is a boolean that determines if this is the first time processNextStart() is being called. If it is the first time, then the traversers are generated. This also simplifies Travaersal.applyStrategies() as it no longer handles traverser generation -- its specific to the step. Once the current profile code is gutted from the core Steps, internal refactoring can be done on StartStep, GraphStep, etc. to make them more simple/compact. Fixed #427. Fixed a clone() bug in FoldStep. Also, bumped to Groovy 2.3.9. Finally, fixed a bug in SackTest and SideEffectCapTest where StandardTest was requiring GraphComputer features.