Adjustable object height, castle surface, forest density and more

[list] [*] Adjustable object height: You can now adjust the height of individual objects. It works with combined objects (e.g. a crate on a tower) and also with multi select, so you can raise or lower several objects at the same time [*] New plot tool "Castle Surface". The height of this tool can be adjusted. More paths and plots will follow [*] Deco images: New function can be set via button. If activated, the images are always imported in the same size ratio. Useful for your own custom assets [*] Density slider for forest added [*] For the roof path, the generation of deco (e.g. chimneys) can now be deactivated via button [*] Minor things [/list]