Overhaul UI: instrument list

t.knopffrequested to merge
overhaul_ui into develop

This MR contains changes of the instrument list towards a more general programming style:

  • InstrumentSelectorWidget is renamed to InstrumentList and does not derive anymore from ItemSelectorWidget, which heavily depends on SessionModel.
  • InstrumetListModel has been implemented as a model for InstrumentList. Currently it uses InstrumentModel as the underlying data structure until that is replaced by something else.

Merge request reports