[Ifeffit] Carlo's problem with wurtzite

[John J. Rehr]

Hi everyone,

 We encountered a similar problem with the default atoms
precision of 5 digits for the  Ti-omega phase structure. For that
structure atoms gave different results for the Wyckoff coordinates:

 1/3   2/3 1/2

and

..3333 .6666 .5 

This (apparently) confused the degeneracy checker in atoms causing atoms
to print out pairs atoms at nearly identical points.

 Although there may be cases where a difference between say 0.67 and 2/3
is a significant distortion, I think it's very rare that crystallographic
parameters are known to better to 4 digits. Thus I'm wondering
whether reducing the precision that atoms demands of a user might
be advantageous.

 J. Rehr