For internal use of SAXO
1) define key_forgetold = 1b - keyword_set(flag)
2) remove all oldcm_used.pro found in !path
3) define and create myuniquetmpdir and add it to !path
4) copy oldcm_full(_empty) to myuniquetmpdir+'oldcm_used.pro'
5) make sure that the common variables are correctly initialized.
6) merge the online_help if possible...