0030655: Modeling Data - Provide interfaces for selection of the elements from BVH...

0030655: Modeling Data - Provide interfaces for selection of the elements from BVH tree

Provide the easy to use interfaces for selection of the elements from BVH tree.
The selection rules should be implemented in the selector class derived from *BVH_Traverse* or in *BVH_PairTraverse* in Reject/Accept methods.

The *BVH_Traverse* is used for selection of the elements from the tree.
The *BVH_PairTraverse* is used for selection of the pairs of elements from two BVH trees.

Auxiliary changes:
- Two methods BVH_Box::IsOut(OtherBox) and BVH_Box::IsOut(Point) have been added;
- Added methods for conversion of Bnd boxes to BVH boxes

Added new class *BVH_Tools* containing useful static methods operating on BVH points and boxes.

The classes BRepExtrema_OverlapTool and BVH_DistanceField have been rebased to use the new traverse methods.