please read...

So I prepared a patch and pushed it to what I thought was my github repo, but actually I pushed it to the main master by mistake. Rather than "fixing git history" and likely causing more trouble, I quickly put in a second patch with something like
if True: 
   # like before
else: 
   # authenticate once
to make my change on the master innocuous at the moment. 

On my github fork however I now have a third patch that makes the change active, that I am asking you to pull to the master after testing. In the end the change is that _init now authenticates only once (readonly for safety) through the connection if the pymongo driver is >= 2.0 (which is when the change in the driver was implemented, at least according to the poor documentation). 
I don't think this fits all the experiments we did, but it does work in practice on both of my machines. So please test on your machines before pulling that change from my fork to the master... Harald particularly, make sure the readonly authentication is not problematic (I could edit a knowl through 127.0.0.1:37777, so it should be okay)