Add variable $vpd containing the viewport camera distance (Fixes #839).
Allow setting $vpt/$vpr/$vpd at top-level to set the viewport camera.
Updated Clipper to 6.1.3a
Some cleanup of old eigen2 workarounds. Added fix to support cameras looking down the Z axis
Link with the correct C++ library on Mac. Added a fix for allowing folder names with regex special characters
#840 Adjust default camera distance after changing FOV to 45 degrees
#840 bugfix: Small axes had wrong rotation, adjusted size of the big axes after changing FOV to 45 degrees
#810 removed unused code
#840 bugfix: Set the up vector to Y axis in the case where we're looking down the Z axis
Merge pull request #841 from openscad/viewport-variables

Add $vpd and make the viewport variables writeable
Added View->View All menu entry
Handle cwd as outputdir
Add test case for issue 835
Resolve #835
debugging messages. update diffpng
Merge branch 'master' of github.com:openscad/openscad into test3dexport

Conflicts:
	src/CGALRenderer.h
	src/GLView.cc