Instantiate an instance of the GoogleCheckout MerchantCalculations prototype

Examples:

@param {Object} objGoogleCheckout an instance of a `GoogleCheckout` object object
@return {Object} Polling Object
@api public
function MerchantCalculations (objGoogleCheckout) {
	var self = this;
	
	//todo: check the constructor name
	assert.ok(objGoogleCheckout, "A GoogleCheckout object is the only required argument");
	
	self.gc = objGoogleCheckout;
	self.settings = self.gc.settings;
}