Added source code and assets

A friend as fallen on some real hard times and is in desperate need of some help so I've added the source code and put this back on paid. If anyone wants to help out someone who really needs it I'd appreciate it. Either way I'll make it free again in a while. 

I'd been considering putting up the source code for a while. The only real downside is the embarrassment of my amateur code which is a silly reason for having not done so. Maybe someone will find some of it handy.

No updates have been made to the game. I don't even know if it'll compile in the current version of Unity. It's been ages since I've worked on it, or indeed any programming unfortunately.