Concerns have been raised that including logging functionality makes it harder
to audit the implementation to ensure that no secret information is leaked. We
are therefore removing it from the master branch.

Initialise the length fields of the reader struct in decode_message, even if the message is invalid, fixes a crash where the message was too short

Rename axolotlpp as olm to avoid confusion with Axolotl-the-spec and Axolotl-the-OWS-libraries at moxie's request