Add a button in 'peak' panel to change all shapes

We would need one more button in the peak panel menu


that allows to change the shape of all the peaks at once.

Only the selected values should be changed using a dialog box similar to:


Note: If we select pseudovoigt the 'mu' parameter appears, otherwise not.

We don't have to change all the values. By default all the fields should be empty and as long as we don't put a value it will not be changed. For example we could wish to change the peak shape without touching fwhm.