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

With only 5 points, the plot is deceptive: there is a lot of spurious variation between runs, particularly because `random_state` is not fixed. Sampling up to 30 estimators so sparsely is not helpful in showing the shape of the plot, and takes a relatively long time to run.

It would be more useful to fix the `random_state` to a constant seed, and show `n_estimators` in `arange(1, 10)`.