Only try to adjust trafficClass if the user asks for.

This should lower the possibility to run into the problem when using windows.
See:
* https://github.com/netty/netty/issues/1478
* https://groups.google.com/forum/#!msg/vertx/nYW3Gv8nxiE/0EcNPmvpw0QJ
Use relaxed parser to parse path and query parts out of an uri to prevent IllegalArgumentException when possible.

For absoluteURI() an URI is still constructed and so validated
Fix and add test for UriParser path logic.
Update to netty 4.0.6.Final
Minimize scope of synchronization