dispatch() method contans duplicated code in multiple classes

[bartosz-oczujda]

The dispatch() method in OnceSignal, MonoSignal & DeluxeSignal contains duplicated code regarding type checks for payloads:

        // If valueClasses is empty, value objects are not type-checked.
        var numValueClasses: number = this._valueClasses.length;
        var numValueObjects: number = valueObjects.length;

        // Cannot dispatch fewer objects than declared classes.
        if (numValueObjects < numValueClasses) {
            throw new Error('Incorrect number of arguments. ' +
                'Expected at least ' + numValueClasses + ' but received ' +
                numValueObjects + '.');
        }

        // Cannot dispatch differently typed objects than declared classes.
        for (var i: number = 0; i < numValueClasses; i++) {
            // Optimized for the optimistic case that values are correct.
            if (valueObjects[i] === null || valueObjects[i].constructor === this._valueClasses[i])
                continue;

            throw new Error('Value object <' + valueObjects[i]
                + '> is not an instance of <' + this._valueClasses[i] + '>.');
        }

Code duplication can be removed by delegating this logic to another class i.e. PayloadValidator