* Add double vote detection to spanner
* Add documentation
* Update slasher/detection/attestations/spanner.go
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-spanner-double
* Merge branch 'slasher-spanner-double' of https://github.com/0xKiwi/Prysm into slasher-spanner-double
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-spanner-double
* Gazelle
* Add double vote detection func
* Implement double voting detection
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-implement-double
* Merge branch 'master' into slasher-implement-double
* Merge branch 'slasher-implement-double' of https://github.com/0xKiwi/Prysm into slasher-implement-double
* Fix typo
* Remove filter, replace with slot + committee index
* Change bloom filter to 2 sig bytes
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-change-filter
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-implement-double
* Merge branch 'slasher-change-filter' of https://github.com/0xKiwi/Prysm into slasher-implement-double
* Change detection to use prefix
* Fix runtime
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-implement-double
* Fix bug and comments
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into slasher-implement-double
* Fix flaky test
* Merge branch 'master' into slasher-implement-double
* Improve logs
* Merge branch 'slasher-implement-double' of https://github.com/0xKiwi/Prysm into slasher-implement-double
* Add ok check
* Fix test
* Merge branch 'master' into slasher-implement-double