Moved all of the Plot Gallery app icons and launch images into asset catalogs.
Moved all of the CPTTestApp app icons and launch images into asset catalogs.
Moved all of the AAPLot app icons and launch images into asset catalogs.
Moved all of the StockPlot app icons and launch images into asset catalogs.
Moved all of the DatePlot app icons and launch images into asset catalogs.
Moved all of the DropPlot app icons and launch images into asset catalogs.
Moved all of the MinorTickFormatter app icons and launch images into asset catalogs.
Moved all of the RangePlot app icons and launch images into asset catalogs.
Merge branch 'master' into release-2.0