[REFACTOR] renamed peak map explorers
[FEATURE] peakmap explorer replaces chromatogram explorer in workbench variable explorer
[FEATURE] drag rect with shift key in peakmap explorer implemented
[FEATURE] Esc behaves as Backspace in plots
[FEATURE] zoom history naviagionin peakmap explorer
[FEATURE] added history list + more navigation in peakmap explorer
[FEATURE] label Gamma -> Contrast Value in peakmap explorer
[FEATURE] vertical cursor in chromo plot in peakmap explorer
[FEATURE] little improvement on rect tool in peamkamp explorer + axis labels
[FEATURE] added input fields and sliders for image range in peakmap explorer