AdaptiveKDTree: make several functions non-static so they show up in profiling; also use BoundBox a bit more
BVHTree: account for BoundBox change
SpatialLocator: choose tree type based on contents of myElems, and move tree construction to a separate function
BoundBox: change name of contains_box to intersects_box, and fix logic that was broken there
TreeStats.hpp: improve statistics output
test_boundbox: fix tests for changes to BoundBox