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

I did this:
```
class GaussianRandomProjectionHash(ProjectionToHashMixin,
                                   GaussianRandomProjection):
    """Use GaussianRandomProjection to produce a cosine LSH fingerprint"""
    def __init__(self,
                 n_components=8,
                 random_state=None):
        super(GaussianRandomProjectionHash, self).__init__(
            n_components=n_components,
            random_state=random_state)
```
But still getting the same error.