Refactoring #1490

Updated by pospelov about 4 years ago

* get rid of ColorMapPlot
* create new widget for projections
** take care of auto margins in QCustomPlot
* equip ColorMapCanvas with uniform right-mouse-button context menu
** introduce same context menu in ImportDataView, FitComparisonWidget for uniformity
* Split presentation of intensity data on 3 types: ColorMap, Projection, FitData
* take care that hidden presentation types do no receive signals and so do not degrade performance (!)
** this can be probably done centrally on the level of SessionItemWidget

* *almost bug* ColorMapPlot should be functional if it's IntensityDataItem suddenly has OutputData<double> pointer to be zero.
** Think of removal IntensityDataItem::getOutputData, ColorMapPlot shouldn't be aware of OutputData<double> and should work only with IntensityDataItem