+ update x64 installer
+ improve error handling when rendering a raytracing project
+ update ReadMe and ChangeLog
Arch: disabled buggy wall auto-corners function
+ add further log messages at startup for better troubleshooting, fix possible crash, fix typos
+ workaround for issue with group separator
Add default for path to OpenSCAD on Mac OS X
Raise exception if the OpenSCAD executeable is unavailable
importSVG: recognize relative scaling in viewBox attribute