WebSocketSocket as flexible WebSocket backend

This is the solutions for issues #7 and #14 

The idea is to introduce a new class which represents a one-to-one connection.
This class is called WebSocketSocket and wraps the net-Socket object in addition of en- and decoding ws frames. The server can easily handle multiple connections by looping through an collection of WebSocketSocket objects.

Current features/issues are currently not solved

* WebSocketBase tests are not applied to new WebSocketBase tasks
* extensions support not given
* in reality not usable (Chrome returns WebSocket-Accept mismatch)
* documentation is not available
* client is not modified