Tasks, cheats, smoke and horns

Update 0.3

 - Finished gravel texture around tracks
 - Adjusted the physics to make it a bit more forgiving
 - Added smoke to the engine
 - Added cheat system
 - Added rail cam - a railside camera that follows the train
 - Made the camera shake whenever the train goes near the railcam
 - Added some missions and tasks
 - Added a horn

I've been working on the task system to iron out a lot of bugs. It took some time, but I finally put some more tasks and missions into the game. I've also added a cheat system. I've only got one cheat ATM but see if you can guess it (Hint: think of the Simpsons episode "Bart vs Australia"). I added smoke particles to the engine, and also a horn.

What's next?

 - Saving/loading
 - Improving the ore spawner, and possibly more ores
 - Improving the UI