Excessive memory usage of large hash_maps

[pcarlini@unitus.it]

> Didn't realize you were doing that!  I was planning to rewrite the TR1  
> version of hash tables once we'd set up the infrastructure for where 
> we'll put TR extensions. 
 
Oh! In that case we all look forward to see your implementation! 
 
In fact we discussed the issue only briefly: I remember a message from Petur 
and a few other... 
 
By the way: what about the first specific issue put forward by Paul? It 
seems that would need a minimum_load_factor that we dont plan to have, right? 
 
Thanks, 
Paolo.