Gui: add coinRemoveAllChildren to work around Coin3D bug

See bug description:
https://bitbucket.org/Coin3D/coin/pull-requests/119/fix-sochildlist-auditing/diff

Because of path based rendering (SoFCPathAnnotation) in mouse over
highlight, this bug causes crash more frequently here comparing to
upstream.

All C++ calling of SoGroup::removeAllChildren() is replaced by
Gui::coinRemoveAllChildren(), and python code is fixed by monkey
patching SoGroup.removeAllChildren() in FreeCADGuiInit.py.

src/Mod/Inspection/Gui/ViewProviderInspection.cpp

@@ -232,7 +232,7 @@ void ViewProviderInspection::updateData(const App::Property* prop)
                 }
             }
 
-            this->pcLinkRoot->removeAllChildren();
+            Gui::coinRemoveAllChildren(this->pcLinkRoot);
             this->pcLinkRoot->addChild(this->pcCoords);
             this->pcCoords->point.setNum(points.size());
             SbVec3f* pts = this->pcCoords->point.startEditing();