Create stand-alone FitDialog function

(1) FitDialog – this is the GUI fitter. I want this to be a stand alone function. See FitDialog/fit_dialog_annotated_TAK_AS.py for starter code I want Inputs: array of wavelengths array of intensities, same length as wavelengths array of uncertainties (optional – not sure that this is currently being used in the example) Output: Astropy model. I think this is called model in the code Other things: Make it possible to delete components (right now you can only add them). Maybe work on formatting for the display

(1) A GUI to which you can supply a sample spectrum and them interactively add spectral components (mostly gaussians and linear backgrounds) and get out a fit structure which serves as a template for future fits. This fit structure can be understood, altered, saved and restored outside the GUI too.