this is a change for functionality that will almost never, ever be used
in practice. but i just didn't like the idea of the 'aging-memory-store'
function creating a thread that you then had no control over whatsoever
after it returns ... maybe someone, somewhere will benefit from this.
the events function stuff always seemed very overkill to me. i cannot
think of any other criteria i've ever wanted for session expiry other
than "expire based on some period of idle time elapsing" and an event
function being used to provide this seems a bit too much to me.
thusly, this has all been replaced with a simple ttl value (specified
in seconds) as a non-optional argument to aging-memory-store.
also change the aging-memory-store opts parameter, it must now be an
explicit map if provided
Gered