New benchmarks

Continuing the discussion on #6 I created a benchmark for gamma calculation. 

I found that (and if everything is correct) if we have a 32 bit index (which is actually enough to store all available IPv4 addresses) we can get only **1 gamma**, in **1 sec** (run was on my virtual machine, so I expect much better performance in a native machine). So this actually means that if we want to calculate 100 indices we need 100 seconds...

I include also a naive approach (read the files for more) that is doing the same thing in **1,6 secs**.

Please review because I think the gamma calculation in the ```server/store.py``` is different than mine?!