private static double fpow(double base, double exponent) {
        if (base < 0) {
            return Double.NaN;
        }
        return exp(exponent * ln(base));
    }
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