unification of plot and settings widgets, as well as polymorphism instead of inheritance
and composition. This will help maintaining the code clear and readable.

This is still a draft commit, let's say. I started doing the unification in the euphonicmodel.py
and in the structurefactorwidget.py - but the files, imports and everything need to be fixed

Putting init in the model, to inject correct traits.

Missing several things:

- energy units conversion
- qplanes
- downloads.

the c extension is needed to speed up the calculation of the
INS spectra.

otherwise we cannot submit any vibro calc.

now local computer is `localhost-hq`