private static double mxatan(double arg)
    {
        double argsq, value;

        argsq = arg*arg;
        value = ((((p4*argsq + p3)*argsq + p2)*argsq + p1)*argsq + p0);
        value = value/(((((argsq + q4)*argsq + q3)*argsq + q2)*argsq + q1)*argsq + q0);
        return value*arg;
    }
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