Replacing gaussian_flux and gaussian_flux_err variables/headers names

[Vital-Fernandez]

In a nearby future update, LiMe will include support for Lorentz/Cauchy and Voigt profiles. This has required the following updates:

• Include the LmFit models for these profiles and make sure LiMe switches automatically with the line label profile suffix.
• Include a "default profile" in LiMe as a global variable. By default this is "p-g-emi" (Gaussian emission). But the users should be able to change the default global profile without the need to specify it on the LiMe notation (although I am still not sure if this should be included on the log measurements)
• Automatically switch the plotting functions to the corresponding model to reconstruct the profile.

These are backend changes which should not affect most users but at this point we should also change the name of the gaussian_flux_err variables/headers in the output measurement files. This is a small change but it is likely to affect users (better to do it before the release).

I was thinking of always leaving the output columns in similar positions and independenlty of the profile use the same variable name. I was planing in replacing the gaussian_flux and gaussian_flux_err by profile_flux and profile_flux_err. Another options could be curve_flux, fitted_flux...

[Knusper]

Changes that break the API are OK, as long as they are proper documented and announced.

However, what I don't understand is, why gaussian_flux can not remain gaussian_flux, whereas the profiles fitted with other profiles are named lorentz_flux etc. - a general profile_flux could still exist, which just points to either one of these... But again, I'm OK with such an incompatible change, as it is just a matter of search and replace in code using this library. I vote for profile_flux.