[horde] [imp] memcache session tracking

[Liam Hoekenga]

>> Since memcache items are just key / value pairs,  how do you iterate
>> through the memcache sessions? Do you keep a list of them someplace?
>
> Yes.  As conf.xml explains, there is a slight amount of overhead since 
> we need to store these keys at the beginning of a session in an 
> internal memcache key.  We also need to do garbage collection every so 
> often to keep the size of this lookup table down.)
>
Is there a utility inside of horde  or a command line script that allows 
us to query the master session key?
Is that key just a list of active sessions ids?  Does it contain other 
information (anything equivalent to the SQL session handler's 
"last_modified" field)?

Liam