simplify coupling between data and instruments
After loading a data file we need to associate it with an instrument model. Currently, we choose one from the list established in the instrument view. If the detector size differs, then we are prompted for confirmation that instrument model may be adapted to the data file.
This is debatable from a UI perspective, and awfully complicated from the coding perspective.
Proposed solution: After loading a data file, we have two options: Either associate an instrument model from a sublist that comprises only those models that have the right detector size. Or create a new instrument model with detector defined by the data grid.
This should allow us to get rid of some signalling.
