ws and wss suport for test method

[jhercog]

Right now linkify.test('wss://example.com/event') returns false. Also, there is no 'type' argument for testing against WebSocket urls.

Please validate urls with wss/ws scheme as true or include the type argument which would make it so E.g. linkify.test('wss://example.com/event', 'websocket') or similar.