add PRINT CRITICAL DENSITY command
A frequently asked question is: what is the critical density for collisional de-excitation of level xxx in some atom or ion. The answer changes every time the atomic data is updated. So it would be useful to have a print command that gives this information based on the atomic data that is in Cloudy. The syntax could be something like
PRINT CRITICAL DENSITY [ levels = n ] [ Te = T ]
which would print the critical density for the lowest n levels (excluding the ground level of course). The default for n could be 5 and the default for Te could be 10,000 K.