Fix the behaviors.lua random function

[slatian]

Sometimes the arguments to the random function in behaviors.lua are swapped because of negative coordinates, this commit introduces a wrapper for the random function which makes sure that math.random gets its arguments in the correct order.

[appgurueu]

An alternative, simpler fix is to simply swap the arguments (see #61); width will be positive. I also found another place where the range may be swapped (horses) which did need a "patched" random function.