TYRUS-302: introduced methods with type parameters to be able to register lambda based message handlers.

@see TyrusSession#addMessageHandler(Class<T>, MessageHandler.Whole<T>)
@see TyrusSession#addMessageHandler(Class<T>, MessageHandler.Partial<T>)
[maven-release-plugin] prepare release 1.6
[maven-release-plugin] prepare for next development iteration
1.6 release