Added spin flips on wall bounce for UCN.
Fixed bug which effectively disabled diffuse UCN reflection.
Wall hit counter now actually counts wall hits.
Added support for CGAL 4.3.
Particles do not produce numerical errors anymore when they happen to be
inside a previously ignored solid when it appears.
Removed old KD-tree based collision detection.
Fixed in-file reader function.
End-of-file was handled incorrectly. Fixes #9.
Fix spin flips
Apply polarisation after each step to correctly calculate equation of
motion after spin flips.
fixed new merge errors with PENTrack with spin flip on wall bounces
editing label in config.in