Control the order of layers selected in the qlr-browser

[MieWinstrup]

Improvement suggestion from Novafos Forsyning:
When you select more layers at once from the qlr-browser, it would be useful if these layers are added to the layer panel in the following order:

1. Raster layers (if any rasterlayer(s) is/are selected in the qlr-browser)
2. Polygon layers (if any polygon layer(s) is/are selected in the qlr-browser)
3. Line layers (if any line layer(s) is/are selected in the qlr-browser)
4. Point layers (if any point layer(s) is/are selected in the qlr-browser)

If this rule is applied, and the user selects a point layer and a polygonlayer, the pointlayer will be displayed on the top of the polygon layer (and the polygonlayer will not hide for the pointlayer).

Maybe it should be a thing that is activated/deactivated in the setting-dialog.