removed some debug defaults and updated UI to FS modifications
- made Steel independant of the level's scenemanager.
-- there can still be a single Level used at once, different ones can be created/loaded/deleted while another one is in use (allows for preloading and post offloading)
- made the UI independant of the current level (sort of: it needs a level to be displayed, but it does not need to be shutdown when switching level anymore).
add triangular terraforming brush
- Engine::etCurrentLevel now auto loads the level
- fix Engine::setCurrentLevel returning pointer to current level.