Maestro: Checking Point/Line or Area should automatically add a new display style

[ksgeograf]

When checking the "Display lines" checkbox on a layer, Maestro should add a default style to the list, if it is otherwise empty.

This should be done for points and areas as well.

Adding this will make it much easier for newcomers to understand how styling works in MapGuide.

[ksgeograf]

This is now fixed.