wing angle corrected from ~70 deg to 92 deg
adjusted cutouts so length "b" in the spec is correct
(this causes the cutout to not align with the end so it
doesn't look as pretty, but the spec wins, right?)
Changed construction method to avoid z-fighting which gave
rise to failed render
doc fixes and shifting in paths.scad
decompose_path -> polygon_parts
bevel is always set by thread depth
acme takes tpi
square threads are at angle 0
added generic_threaded_{rod,nut}
eliminated metric_trapezoidal_*
cleaned up matrices some in generic_threaded_rod
threaded_rod can produce spec-true ISO/UTS profile with a triplet input for the diameter.
Added bevel1 and bevel2 to all modules. Made default uniformly false for every case instead of
sometimes true, sometimes false
Profiles that go over zero are not clipped, and bevels are based on actual profile top, not nominal
When bevel is given to nuts it bevels the outside of the nut by thread depth
higbee looks best with quincunx, but it's more expensive. Select quincunx when higbee is used, min_edge otherwise
Current code uses difference to remove excess length in the rod. This gives faster renders at the cost
of more complex code and green top/bottom surfaces.
Changed slop to 4 * $slop. I got good results printing with $slop=0.05 with this setting.
Don't generate excess threads when starts>1, and don't force threads to be even
