ALPN / NPN need to handle no compatible protocols found

Motivation:
If there are no common protocols in the ALPN protocol exchange we still compete the handshake successfully.  This handshake should fail according to http://tools.ietf.org/html/rfc7301#section-3.2 with a status of no_application_protocol.

Modifications:
-Upstream project used for ALPN (alpn-boot) does not support this.  So a PR https://github.com/jetty-project/jetty-alpn/pull/3 was submitted.
-The netty code using alpn-boot should support the new interface (return null on existing method).
-Version number of alpn-boot must be updated in pom.xml files

Result:
-Netty fails the SSL handshake if ALPN is used and there are no common protocols.
Ah I see.  Would it make sense to replace the factory accessor methods with the factory methods themselves (i.e. make the factory methods top-level methods in the negotiator interface)?