* Changed management of candidates in internal nodes: Node.insertCandidate -...

* Changed management of candidates in internal nodes: Node.insertCandidate - replace the closest candidate with the new (better (farther)) candidate
* Changed default of recomputeDuringSplit to false -- if true, it checks and changes candidates among siblings in Node.getRelevantCandidateHullObjects
* Change: When a node is split and the new nodes fit into the parent, the parent's hull is updated with candidate objects.
* Change: internal node's isCovered test takes into account the candidates in a way that an object non-covered by hull is taken as covered if its rank is smaller than at least one candidate of the node.

* Added cmd args for recompute during split/insert
* Minor code clean-up