ptg: use hastable instead of set

We'll use that space anyway and it's faster. Moreover, it will
allow to get points-to set of a pointer easily from the pointer
ptg: introduce getNode function

Until now, finding out if a node exists and creating new in the case
it doesn't required accessing Nodes 2 times. This function returns
existing node and in the case it had not existed before it creates
one in one access.
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)
ptg: use SmallSetVector for node's edges

it's faster
ptg: add Node::getCategory

allow to quickly find out, what is the category of pointers in a node
ptg: use normal array for edges

Since having lot of edges is not efficent, constrain it to NODE_EDGES_NUM number
(currently 8). This allows us to use normal array which is faster that using iterators and mapping from nodes to this array (index in array is node's category)
ptg: use set again for elements

toPointsToSets assume the elements are sorted so that's one reason.
The another reason is that now I can simply get the points-to set from
the PTG without converting the node
fix gep
ptg tests: fix AllInSelfCategory

GEP can add new pointers which are not in valueMap. This broke
getCategory method.
ptg: remove areInSameCategory method

this method has been replaced by getCategory everywhere and is useless now
PTGTester: use MapVector for valuesMap

We need the same order in map as is the insert order
(due to getCategory that relies on it)
PTGTester: fix check

check was not returning false when it should have
tests: update

remove tests for recently removed areInSameCategory and add new tests
for toPointsToSets and building graph.