Adding features for Sigs, chords, groups, chains

 - Adding support for message format protocol V1 and V2
 - Chords, Chains, Groups are of Signature
 - Message moved to \Rhubarb\Task namespace it seemed to make no sense
   to reside on its own as it is only a utility class for handling
   composition of the outgoing messages.
 - Examples for Chords, Groups and Chains build to facilitate
   documentation, test and subsequent coding.