bloom-filter based minimal perfect hash function library

 BBHash is a simple library for building minimal perfect hash
 function. It is designed to handle large scale datasets. The function
 is just a little bit larger than other state-of-the-art libraries, it
 takes approximately 3 bits / elements (compared to 2.62 bits/elem for
 the emphf lib), but construction is faster and does not require
 additional memory.