addExtensions = function addExtensions(type, extensions) {

	// type does not exist
	if (!Extensions[type]) {
		return null;
	}

	for (var name in extensions) {

		if (!extensions.hasOwnProperty(name)) {
			continue;
		}

		// name already exists 
		if (Extensions[type][name]) {
			return null;
		}

		// register
		Extensions[type][name] = extensions[name];
	}
}
Adds multiple extensions in one go
@param type
@param extensions
@returns {null}