Finally added support for users to define custom fitting templates.
Summary of code changes:
Moved the EISFitTemplate class to its own file
Greatly expanded the allowed initialization parameters
Added validation and self-consistency checks
Added support for loading a custom template from a TOML file
Fixed a small bug in reading the template wmin and wmax values (previously was estimated from the example spectra, rather than reading the actual values in the template)
Finally added support for users to define custom fitting templates. Summary of code changes:
EISFitTemplateclass to its own file