[imp] memcache session tracking

[Liam Hoekenga]

Hey -

I'm a little out of touch with the CVS version of Horde.  I notice in 
May that "session tracking" was added for the memcache session handler, 
but it's not totally clear to me what that actually means.   The biggest 
thing I miss about using the MySQL session handler is the ability to 
build usage statistics based on periodically querying the last_modified 
field.. and while I can get stats from my memcached server, the number 
of cache items doesn't directly equate to the number of active sessions.

Will the mecache session tracking allow me to get that sort of usage 
information?  If so, will it work across a pool of memcache servers?

Liam