Add Weighted Jaccard Similarity LSH family

**What similarity measure is this hash function for?**
[Weighted Jaccard similarity](https://en.wikipedia.org/wiki/Jaccard_index#Weighted_Jaccard_similarity_and_distance)

**References**
- *Improved Consistent Sampling, Weighted Minhash and L1 Sketching* (Ioffe, 2010)
- *Exact Weighted Minwise Hashing in Constant Time* (Shrivastava, 2016) ([arXiv:1602.08393](https://arxiv.org/abs/1602.08393))