improvements in the phonowidget

### Phonons tab
- [ ] Where do the Q-point labels come from on this plot - they don't obviously agree with the list of special k-points for this space group given by the Bilbao crystallographic server for example. It would be useful to be able to look them up and understand in what basis/coordinates they are expressed. - toogle info button with the data.
- [ ] It would also be useful to change the units of this plot to meV as well, though I agree this is sort of available in the neutron scattering tab.