Add abstract method to base clas

Author: gonzalocasas

src/compas/artists/meshartist.py

@@ -326,6 +326,10 @@ def draw_faces(self, faces=None, color=None, text=None):
         """
         raise NotImplementedError
 
+    @abstractmethod
+    def draw_mesh(self):
+        raise NotImplementedError
+
     @abstractmethod
     def clear_vertices(self):
         raise NotImplementedError