Difference = function (a, b)
{
    return Math.abs(a - b);
}
Calculates the positive difference of two given numbers.

@function Phaser.Math.Difference
@since 3.0.0

@param {number} a - The first number in the calculation.
@param {number} b - The second number in the calculation.

@return {number} The positive difference of the two given numbers.