Refine model creator plugin framework for scripting context, use in all model plugins, add to scripting example

[dbenn]

Are few things are needed here:

• Implement setParams() for all model creator plugins. Only polyfit does this currently.

• The current common model creator function in VStarScriptingAPI should return an array of double values, e.g. uncertainty values. We return an array of doubles from the dcdft scripting API functions (for example). It could be empty or NULL. The plugin itself may need to implement a getOutputValues() method or similar as well.

  • May also want to add a model creation parameter to dcdft scripting API functions since Fourier analysis alone is not enough to yield uncertainties (need peridogram data and residuals). The uncertainties could then be added to the values returned along with top-hits or we allow the created models (exposed in the UI via the Models dialog) to be queried, e.g. by model name, number.

• Move the kind of needGUI logic in polyfit to the base model creator plugin class and make use of in plugins.

This issue was prompted by a question to Bert from a VStar user about scripted Fourier model creation. I started to do adapt this script:

https://github.com/AAVSO/VStar/blob/master/script/JavaScript/example_vstar_script.js

then realised it would not have the desired effect yet.

[dbenn]

See also https://github.com/AAVSO/VStar/issues/44 but this doesn't really give us what we want: an array of double values.