All files in src/ apart from Rgeometry.h, Rconvhulln.c, Rdelaunayn.c
Rtsearchn.c, Rtsearch_orig.c, Rtsearch.cpp, RcppExports.cpp,
Rinhulln.c, Rhalfspacen.c and geometry_init.c are taken from or based on Qhull
(http://www.qhull.org/), and covered by COPYING.txt.
