Progressive Difficulty: Mobs

Changed spawn height filter to be limited to the min and max world height instead of a static 0 and 255 Existing monsters with this exact spawn height filter (min 0 and max 255) will be updated to the new world height (usually -64 and 320) Development for the plugin is unfortunately stopped because I think there's some issues with the core design of the plugin. It's still functional and if configured properly can be a lot of fun. The plugin will still be maintained, but I found it to be too hard to use for server developers and too hard to understand for players and will be attempting a simpler design in the future that can hook into ValhallaMMO (also working standalone)