add spectral lines to a model

Tcl script to add one or more lines to the current model in an optimum fashion.

Syntax: addline [<nlines>] [<modeltype>] [fit|nofit]

<nlines> additional lines are added one at a time. Line energies are set to that of the largest residual between the data and the model. For each line a fit is performed with the line width and normalization as the only free parameters. The default option is one gaussian line. The other <modeltype> that can be used is lorentz. If no third argument is given then the sigma and normalization of each line are fit. If nofit is specified then the fit is not performed but if fit is specified then all free parameters are fit.

addline currently will only work with the default model (i.e. not for named models).