checkCIF procedure

PLAT909

 This ALERT Reports on whether there is still a significant level of observed
 data beyond the Theta cutoff of the Dataset. There should be a good reason
 for a cutoff below sin(theta)/lambda = 0.6 Ang**-1. Reflection data beyond
 that value should not be removed when significantly above the noise level.
 E.g. they may be very relevant in case of pseudo- symmetry and
 (non)centrosymmetry refinement.