suggestion to add titles to columns in g_principal output files
Suggestion to add comments with titles for each column to axis1.dat axis2.dat axis3.dat and moi.dat out of g_principal.
See, for example, the following post that outlines how, without titles, the current output is counter-intuitive:
Fixed the output format of g_principal
Gromacs-4.6 and earlier versions had the output transposed. This
patch fixes it such that paxisN.dat contains the x/y/z components
of the N:th prinicipal axis. The default file output names have
been changed to paxisN.dat to increase the probability that users
who rely on old scripts will need to read the help text and find
the changed format.