Refactored the use of epsilon in the clamping of the start/end points of the LineSegmentIntersector to better handle numerical precision issues.
From Farshid Lashkari, "The ProxyNode serializer was not correctly reading the "Children" field. It conditionally writes the begin/end brackets, depending on whether it has children. However, during input it unconditionally attempts to read the begin/end brackets. I've modified the code to only read the brackets if it has children."