Fix some typos

This should fix clang/gcc build errors.
Fix int+char* instead of to_string(int)+char*
Disable CEGUI RiseOnClick by default for images

Also sort the gui/ folder a little and update the config to reflect the
changes.
Implement InputSwallowerManager
Implement BasicCamera
Implement CameraManager::onLevelLoad
Implement LevelManager::runPostInitEvents()
Remove some counter-productive "#if DEBUG"s
Fix Level::addThing typos

That happens when you write 20,000 lines without being able to ever run
the damn code.
Comment out LuaMain functions temporarily

Since they just don't work and are still called from everywhere, that's
pretty much the only sane thing to do.
Add RaceCountdown header guards
Implement new Kart methods, event unsubscribing

We now use IDs::incremental as a GUID to unsuscribe from some events.
Fix bug in direntSearchRec
Implement Kart::postInitialiseComponents
Change position/target of the default BasicCamera

So that it's looking at the finish line in SAA
Update gitignore
Upload fixed media/ folder

- Removed some unused assets
- Fix/simplify the used materials
- Fix a broken .thing in SAA (SAA_Road_Combined)
Add the SceneEnvironmentHandler
Fix linux premake script, errors
Fix linux errors, use after free

Fix use after free in LThing's constructor

Fix build errors on Linux

Various minor changes