HyperLogLog++ cardinality estimation algorithm

 hllpp is an implementation of the HyperLogLog++ cardinality estimation
 algorithm in go. It optimizes for memory usage over CPU usage. It
 implements all the HyperLogLog optimizations introduced in the
 HyperLogLog++ paper (http://goo.gl/Z5Sqgu). Some notable features include:
 .
  * Marshaling so you can serialize to your datastore,
  * Extra space savings by only using 5 bits per register when possible,
  * Built-in non-streaming murmur3 implementation for fast hashing of input
    data.
 .
 This is the dev package.