Clickable controls! Muffled interior sounds! Turbo & Nitro upgrades for extra speed!

I added a couple new upgrade modules for the boilerbox!
– Turbo Upgrade: It shoots lava into the burner at higher pressure, meaning a higher top speed but also increased consumption
– Nitro Upgrade: The nitro upgrade / Blazecake booster consumes "Blazecake Capsules" to give the Boilerbox a brief and high speed boost! Needs to be periodically reloaded though…
– Cab Upgrade: More walls for your cab not only increases aerodynamics, it also shields you from the loud sounds of the engine right behind you!