Groupcache and Sequencer Support
- Added "labelsz" data type, which allows ranking of labels based on number of annotations.
- Added groupcache support with configuration via TOML and HTTP API for stats.
- Added CircleCI support.
- Numerous fixes and documentation clarifications.
Binaries are compiled using Go 1.7. Linux compilation uses gcc-4.8.4 due to lz4 C routines.