Ice rings

• Please see Wishlist#Would be nice to have: there's a list of additional (high-) resolution ranges one might want to exclude (in CORRECT).
• A currently possible way to prevent ice rings from spoiling the IDXREF step is to set "TRUSTED_REGION=0 X" for INIT, where X is calculated such that ice rings are excluded. Using Bragg's law and an approximation, we find that
  X = [math]\displaystyle{ \frac{Wavelength \cdot Distance} {2 \cdot NX \cdot QX} }[/math] should give approx. 4 Å cutoff, which should exclude all ice rings.
  Drawback: after successful indexing, INIT needs to be re-run with "TRUSTED_REGION=0 1.05" or so.

A potential pitfall: the above assumes that the direct beam position is near the middle of the detector.

• Please see Optimization for how to treat remaining ice reflections showing up as "aliens" in CORRECT.LP.