[MeL/Elements] Add non-const getNode().

MeshLib/Elements/Element.h

@@ -55,6 +55,7 @@ public:
      * @sa getNodeIndex()
      */
     virtual const Node* getNode(unsigned idx) const = 0;
+    virtual Node* getNode(unsigned idx) = 0;
 
     /**
      * (Re)Sets the node of the element.

MeshLib/Elements/TemplateElement-impl.h

@@ -109,6 +109,20 @@ const Node* TemplateElement<ELEMENT_RULE>::getNode(unsigned const idx) const
     return _nodes[idx];
 }
 
+template <class ELEMENT_RULE>
+Node* TemplateElement<ELEMENT_RULE>::getNode(unsigned const idx)
+{
+#ifndef NDEBUG
+    if (idx >= getNumberOfNodes())
+    {
+        ERR("Error in MeshLib::TemplateElement::getNode() - Index {:d} in {:s}",
+            idx, MeshElemType2String(getGeomType()));
+        return nullptr;
+    }
+#endif
+    return _nodes[idx];
+}
+
 template <class ELEMENT_RULE>
 void TemplateElement<ELEMENT_RULE>::setNode(unsigned idx, Node* node)
 {

MeshLib/Elements/TemplateElement.h

@@ -189,6 +189,7 @@ public:
     }
 
     const Node* getNode(unsigned idx) const override;
+    Node* getNode(unsigned idx) override;
     void setNode(unsigned idx, Node* node) override;
     Node* const* getNodes() const override { return _nodes.data(); }