Delete functions from DEVS that are deployed in production modules

[ambarb]

DEVS looks to be a proving ground. Sometimes those functions are deleted when they are deployed to "live" modules. Sometimes it is not. I've compared functions and will list here findings.

very safe to delete from DEVS.py

• fit_one_peak_curve ; better function in chi_generic_functionshttps://github.com/NSLS-II/pyCHX/blob/6e991bb1eb06d8fe1bc8f684ebfcec581ee57aba/pyCHX/chx_generic_functions.py#L74
• plot_xy_with_fit ; same function in chi_generic_functionshttps://github.com/NSLS-II/pyCHX/blob/6e991bb1eb06d8fe1bc8f684ebfcec581ee57aba/pyCHX/chx_generic_functions.py#L114
• next function goes here......

need expert eye