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

I think this can be greatly simplified with:

```python

for i, n_estimators in enumerate(n_estimators_for_candidate_value):
    label = 'n_estimators = %d ' % n_estimators
    plt.plot(n_candidates_values, accuracies_c[i, :], 'o-', c=colors[i], label=label)

plt.legend(loc='upper left', font='small')
```