Merge branch 'master' of github.com:ultimaker/Cura into per_object_settings

* 'master' of github.com:ultimaker/Cura: (98 commits)
  15.10 Restyling of the message stack
  Fixed machine head polygons
  Removed unused settings from fdmprinter
  Added action for togling fullscreen
  Fixed usage of wrong checkbox in viewpage
  Added preference to disable automatic push free
  Added preference to disable auto center when selecting object
  Cleanup
  15.10 Restyling toolbar, viewmode button
  Update README.md
  Update README.md
  Added rudementary 3 point bed leveling
  15.10 New font for Cura
  15.10 Changes the styling for the open file button
  15.10 Changes the label names for the different action buttons
  Fixed typo
  Endstop now stops listening upon destruction
  15.10 Re-alignment of the messagestack
  Cleaned up code a bit
  Added heated bed check
  ...

cura/ConvexHullNode.py

@@ -33,14 +33,14 @@ class ConvexHullNode(SceneNode):
         self._hull = hull
 
         hull_points = self._hull.getPoints()
-        center = (hull_points.min(0) + hull_points.max(0)) / 2.0
-
         mesh = MeshData()
-        mesh.addVertex(center[0], 0.1, center[1])
-
+        if len(hull_points) > 3:
+            center = (hull_points.min(0) + hull_points.max(0)) / 2.0
+            mesh.addVertex(center[0], 0.1, center[1])
+        else: #Hull has not enough points
+            return
         for point in hull_points:
             mesh.addVertex(point[0], 0.1, point[1])
-
         indices = []
         for i in range(len(hull_points) - 1):
             indices.append([0, i + 1, i + 2])