Finally found the bug + input changes

By request and a sensible one at that. Space & Enter keys will now also function as fire.

Finally nailed the random number issue when in firefox (I hope). I moved the random number generator to a global scene and called randomize on it once. Previously each point of use of the random number generator was creating it's own and then each one had a call to randomize. SO perhaps the repeated randomize call was initialising to the same position when called - I don't know and I don't know why it was isolated to in browser firefox.