Last release before a session key functionality change

In this version, and in those prior -- the Authentication Entity's session key parameter is base64 encoded in the constructor.

This unfortunately makes creating fixtures very painful -- this release essentially pins that mechanism.

In upcoming versions...

If you were using low-level entities instead of services, you will need to change your codebase just a bit.

The old setSessionKey becomes setRawSessionKey. Constructor invocations must base64 encode the session key at the instantiation point - the constructor will no longer do it. See tests for more.