Revert "Update 3D curve example with the thread-enabled evaluator"

This reverts commit da26e36.

curve3d/ex_curve3d02.py

@@ -13,9 +13,8 @@
 from geomdl import BSpline
 from geomdl import utilities
 from geomdl import exchange
-from geomdl import evaluators
-from geomdl.visualization import VisMPL as vis
-# from geomdl.visualization import VisPlotly as vis
+# from geomdl.visualization import VisMPL
+from geomdl.visualization import VisPlotly
 
 
 # Fix file path
@@ -24,10 +23,6 @@
 # Create a B-Spline curve instance
 curve = BSpline.Curve()
 
-# Set threaded evaluator
-threading_evaluator = evaluators.ThreadedCurveEvaluator(curve.evaluator, threads=4)
-curve.evaluator = threading_evaluator
-
 # Set up curve
 curve.degree = 3
 curve.ctrlpts = exchange.import_txt("ex_curve3d02.cpt")
@@ -42,7 +37,7 @@
 curve.evaluate()
 
 # Plot the control point polygon and the evaluated curve
-vis_comp = vis.VisCurve3D()
+vis_comp = VisPlotly.VisCurve3D()
 curve.vis = vis_comp
 curve.render()