should be peak picking a method of common-spectrum or method specific?

[kjappelbaum]

I started working a bit on the peak picking (https://github.com/kjappelbaum/xrd-analysis) but it seems to me that the code is not really dependent on the specific spectrum type (except for the peak shape). Maybe this should then be moved to common-spectrum?

What do you think @lpatiny ?

[lpatiny]

Maybe but for some spectra (like TGA) you can not make peak picking (except after derivative).
This is why I didn't put it there. But it is through that it could be in common spectrum and we don't need to export it in tga-spectrum for example. We can also when we reexport this method defined default parameter.
You may put it in common-spectrum.