MergeXHRSettings = function (global, local)
{
    var output = (global === undefined) ? XHRSettings() : Extend({}, global);

    if (local)
    {
        for (var setting in local)
        {
            if (local[setting] !== undefined)
            {
                output[setting] = local[setting];
            }
        }
    }

    return output;
}
Takes two XHRSettings Objects and creates a new XHRSettings object from them.

The new object is seeded by the values given in the global settings, but any setting in
the local object overrides the global ones.

@function Phaser.Loader.MergeXHRSettings
@since 3.0.0

@param {Phaser.Types.Loader.XHRSettingsObject} global - The global XHRSettings object.
@param {Phaser.Types.Loader.XHRSettingsObject} local - The local XHRSettings object.

@return {Phaser.Types.Loader.XHRSettingsObject} A newly formed XHRSettings object.