v2.11 - Updated for PostgreSQL 11
v2.10.2 - Updated for PostgreSQL 10
v2.10.1 - Updated for PostgreSQL 9.4 and 9.5.
v2.10.0 - Merged PR #17, cleaned up compiler warnings and test cruft, added binary IO type for hll.
v2.9.0 - Fixed issue #16, bitstream_pack fixed to write one byte at a time to avoid writing to unallocated memory.
v2.8.0 - Fixed issue #2, hll_add_agg now returns hll_empty on input of an empty set. (Thanks to @ozgune!)
v2.7.1 - Build fixes for OS X and Debian. Documentation fixes. Small changes to test format to improve stability across psql versions.
v2.7 - First open-source release.