checkCIF procedure

PLAT766

 
 The final .fcf associated with the .cif should have been created
 with the LIST 4 instruction (or just left out because already implicit with
 the ACTA instruction). The LIST 8 instruction will create an FCF file where 
 the observed data are detwinned making the generated .fcf unsuitable 
 for checking for missed (additional) twinning and validation.