replace WebSocketSocket data parsing with TransformStreams

The current implementation of how we parse and write WebSocket frames is quite custom.

Using TransformStreams would be a standard pattern also we can make things much more clear and maybe deprecate the trash bin class `WebSocketFrame`.

The following changes could help to solve #24, #11, #1.  

First commit is about a standalone TransformStream `WebSocketStream` which normalizes the output of `socket "data"` (unglues, concates data packages to frames) but is not bound to `WebSocketSocket`.