Peak Grouping Depends on Order of samples

[PMSeitzer]

This was discovered during #746

peakdetector always sorts samples by natural order, while the peaks search in the GUI was using the order from the main window.

However, there is an issue with the peak group formation algorithm, where apparently the order of the samples affects the peak groups. This is either in EIC::eicMerge() or EIC::mergedEICToGroups(), though the latter seems less likely since there is a
sort(allPeak...) step.