199 make fitter a part of project

[andped10]

Additions to the Project class to expose functionality to APP.

Minor corrections to other code parts.

Renamed Fitter to MultiFitter because that is what it is

Change name of module paramter_utils.py to utils.py

• introduced new function to collect all unique names in the dicts produced by the sample and model

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[rozyczko]

I think your Project class is generally good.
It owns various important objects - models, materials, calculator, fitter etc.

This will allow a very simple syntax for creating scripts, where the only module you import is Project.
This is pretty much the same approach as we have with Job in diffraction, so I envision merging these two at some point.