0.4: Tutorial revamp and throwing items

I’ve redone the tutorial to try and make it more obvious what you’re supposed to do. Other changes:

• Initiates can attack with flashbangs. Physically harmless, but you don’t want to get hit by them when running for your life!
• You can throw knives, your own flashbangs and smoke bombs in addition to the existing sockpuppet.
• The player footsteps sound different on different surfaces. NPCs now have their own footsteps as well!
• Brightness, contrast, voice volume and mouse speed are now configurable. Special thanks to Galligan for pointing that last one out!