adding unbounded ranges info for IndexRangeNode.
adding RangeInfoBound to clean things up.
starting to add optimizer rules which create IndexRangeNodes.
remove comment and update the toJsonHelper for IndexRangeNode.
added new class to contain ranges, and take their intersections.
AND working for IndexRangeNode.
Merge branch 'aql2' of ssh://github.com/triAGENS/ArangoDB into aql2

Conflicts:
	arangod/Aql/Optimizer.cpp
	arangod/Aql/OptimizerRules.cpp