Have SMAPI ignore marked tilesheets from a modfolder/contentpack when loading the map

Allow map modders to keep certain (vanilla) files next to their map content and still have those loaded from game content.
First proposal was to mark them was some kind of tilesheet property like @IgnoreLocalFile, another to have the file start with a dot, e.g. .fall_town.png.

Done in the upcoming SMAPI 3.10 using the dot-ignore convention. Thanks for the suggestion!