private static int atan(LuaCallFrame callFrame, int nArguments) {
        BaseLib.luaAssert(nArguments >= 1, "Not enough arguments");
        double x = getDoubleArg(callFrame,1,names[ATAN]);
        callFrame.push(LuaState.toDouble(atan(x)));
        return 1;
    }
Rounds to keep <em>precision</em> decimals. Rounds towards even numbers.
@param x the number to round
@param precision the precision to round to. A precision of 3 will for instance round 1.65432 to 1.654
@return the rounded number
main/src/main/java/cgeo/geocaching/wherigo/kahlua/stdlib/MathLib.java