ptg: don't skip arrays

The analysis did not take into account arrays.
One usualy iterate over an array so leaving it unsliced
should be OK. Anyway, I need to compare the new analysis with
the old analysis, so I have analyse even the arrays.
ptg: add getters for size

normal size and count of points-to pairs
ptg: fix hasNeighbours

when an edge was removed, then EdgesNo was not decreased
This lead to return true from hasNeighbours even when no
neighbours were present
ptg: add rebuild method

This method takes new PointsToCategories and rebuild the
Graph according it.

It splits nodes that contains elements
with more than one category and then continues in creating
fixpoint