provide hashtag commands for different relaxation functions

gprMax/hash_cmds_file.py

@@ -209,7 +209,9 @@ def check_cmd_names(processedlines, checkessential=True):
     # Commands that there can be multiple instances of in a model
     # - these will be lists within the dictionary
     multiplecmds = {key: [] for key in ['#geometry_view', 
-                                        '#geometry_objects_write', '#material', 
+                                        '#geometry_objects_write', '#material',
+                                        '#HavriliakNegami', '#Jonscher',
+                                        '#Crim', '#Rawdata',
                                         '#soil_peplinski', 
                                         '#add_dispersion_debye', 
                                         '#add_dispersion_lorentz',