Refactor RippleCalc:
* Rationalize method and filenames, move to subdirectory.
* Use Issue in Node.
* Restrict access to PathState variables.
* Line length and readability cleanups.
* New PathCursor stores path calculation data during rippleCalc.
* Extract methods PathCursor::node(), PathCursor::previousNode()
  and RippleCalc::addPath
More fixes to VSProject sorting algorithm