vector can't be 0,0,-1

[JuhaHuiskonen]

If vector defining the sub-structure is exactly 0,0,-1 vector 0,0,1 is used instead. Current workaround is to introduce a small inaccuracy, e.g use vector 0,0,-0.99. But this should be fixed. @serbanilca

[JuhaHuiskonen]

@serbanilca this is the proposed fix:

--- euler.py.old        2018-01-05 15:59:54.000000000 +0100
+++ euler.py    2018-01-05 16:01:22.000000000 +0100
@@ -58,7 +58,7 @@

     if abs(vector.x()) < 0.00001 and abs(vector.y()) < 0.00001:
         rot = radians(0.00)
-        tilt = radians(0.00)
+        tilt = acos(vector.z())
     else:
         rot = atan2(vector.y(), vector.x())
         tilt = acos(vector.z())