pts-to: add settings for andersen's analysis

when K in computePointsToSets is UINT_MAX,
use AllInSelfCategory (=> andersens analysis)
pts tests: fix memory leak
pts-to: add points-to-perf

tool for measuring running time of computePointsToSets
ptg: user SmallSetVector for node elements

It's faster. Also typedef it, so that later changes will be easy
ptg: add getCategory to PointsToCategories

And move AllInSelfCategory into tests. Using Andersen analysis
is unefficent with this algorithm, but it's good for testing.
ptg: add origin to each node

Store first element in the node and use it as a representat of the node
(in nodes are only elements with the same category)