Writes the .dwg file data of this object. 

This function is called by dwgIn() to allow the object to write its data. 

When overriding this function: 

1) Call assertReadEnabled(). 2) Call the parent class's dwgOutFields(pFiler). 3) Call the OdDbDwgFiler(pFiler) methods to write each of the object's data items in the order they were written.