Added ROT.RNG.getRandomInt(x,y)

This is a simply tweak to allow the incredibly useful ROT.Map.Rogue.prototype._getRandomInt(x,y) function to be used anywhere in a rogue-like relying on rot.js. The only change to that function is a quick check to ensure that the order of arguments doesn't matter, it'll always use the smaller as the lower bound and larger as the upper bound. 

This change includes a recompiled rot.js and rot.min.js but documentation wasn't touched. I also didn't touch any of the code that called either getUniform() directly or _getRandomInt() in case there is a specific reason you didn't include this as a function on ROT.RNG, however I'll go back and update those to use this function if you'd like.