[WIP] Locality Sensitive Hashing for approximate nearest neighbor search(GSoC)

There is no way to understand your intent from this code. Extract the code to a meaningfully named function, or use a comment. 

In terms of implementation itself, it is not as obviously correct as it could be. If max_label_length somehow starts as a float, your code will fail, where int(max_label_length/2)*2 would obviously succeed.

But I think I've mentioned that *in my opinion*, this datastructure has no right to exist unless max_label_length is exactly 32 or 64 (and just 32 is probably sufficient for the moment); there are too many low level inefficiencies these particular cases avoid. That said, if your parameters invite max_label_length=23, you better be testing that it actually works...