function sign(n) {
    if (n === 0)
        { return 0; }
    return n < 0 ? -1 : 1;
}
Returns sign of number
@memberof PIXI.utils
@function sign
@param {number} n - the number to check the sign of
@returns {number} 0 if `n` is 0, -1 if `n` is negative, 1 if `n` is positive