GiD_Event_AfterCreateMaterial: will be called just after create the material 'name'
GiD_Event_AfterRenameMaterial: will be called just after the mateial 'oldname' has been renamed to 'newname'
GiD_Event_BeforeDeleteMaterial: will be called just before delete the material 'name'
If it returns -cancel- the material deletion is cancelled.
GiD_Event_AfterChangeMaterial: will be called just after change some field value of the material 'name'.
GiD_Event_AfterAssignMaterial: will be called just after assign or unassign the material of some entities.
- name is the name of the new material. If it is "" then the material has been unassigned.
- leveltype: is the kind of entity, if could be:
For geometry: POINT_LT, LINE_LT, SURFACE_LT,VOLUME_LT
For mesh: ELEM_LT.