Fix testing of /opt/local, move /usr/local to the front of the list, and break on first found. Check for Sparkle on Darwin
Merge pull request #285 from thinkyhead/master

check-configuration.sh on OS X
Uncatchable CGAL assertion exception
Sparkle build tweak
OpenCSG is now in MacPorts
Merge branch 'master' of github.com:openscad/openscad into issue11_2
update manpage