Slightly faster bucket lookup
Some performance improvement

Adding some benchmarking, but also a tweak which gets rid
of the exponential bottleneck. Pre-computes a unique hash
per vector, stores that, and uses that for uniqing.

Still very experimental though...
Cleaning the code
Using a hash to make sure results are unique
Removing time logging
Removing uniq test
In multiprobe test, vector needs to be added first
Fixing memory storage tests
Using vector.hash (using monkey-patching of GSL)
Returning hashes and ids as part of results
Making Redis backend work with optimisations
More statistics in evaluation script