* implement UTF8 handling
or to be precisely, we add UTF8 validator which main duty
is to detect malformed UTF8 sequence using a fast DFA UTF8
decoder.
also enable autobahn UTF8 category tests, much more green :)
fixes#13
* fixes case 7.5.1 Send a close frame with invalid UTF8 payload
* add tests for validateUTF8
- tests for validateUTF8 in raw mode
- tests for validateUTF8 in websocket client/server
