improve support for DPI scaling ScottPlot#563

DPI state is no longer stored in the plot settings module, but instead handled at the control level.

This change fixes draggables which were previously broken.

WPF users wanting to use ScatterPlotHighlight must get coordinates using wpfPlot1.GetMouseCoordinates() as seen in the demo application.

fix DateTime test on OSX

OSX can only instantiate DateTimes between 04/30/1900 and 11/16/2077 ScottPlot#561, ScottPlot#564

ScottPlot 4.0.40

ScottPlot 4.0.39

update cookbook notes

ScottPlot 4.0.37

ScottPlot 4.0.36

Update changelog.md

somehow I got confused and didn't issue new releases when I thought I did... so 4.0.35 is all the sudden a big release

Update changelog.md

Update changelog.md