Pure Erlang bloom filters extracted from riak_core for reuse.

%% Based on
%% Scalable Bloom Filters
%% Paulo Sérgio Almeida, Carlos Baquero, Nuno Preguiça, David Hutchison
%% Information Processing Letters
%% Volume 101, Issue 6, 31 March 2007, Pages 255-261
%% Provides scalable bloom filters that can grow indefinitely while
%% ensuring a desired maximum false positive probability. Also provides
%% standard partitioned bloom filters with a maximum capacity. Bit arrays
%% are dimensioned as a power of 2 to enable reusing hash values across
%% filters through bit operations. Double hashing is used (no need for
%% enhanced double hashing for partitioned bloom filters).

%% modified slightly by Justin Sheehy to make it a single file
%% (incorporated the array-based bitarray internally)