[Feature Request] Expose 128bit murmur3 option

[mbarretta]

The underlying Murmurhash3 library supports the currently utilized 32bit variant as well as a 128bit variant. When dealing with very large indices (billions to trillions of records), the 32bit variants leads to common hash collision. This should be much less prevalent in a 128bit keyspace.

[mbarretta]

dup, doh. closing.