* Add flag for attester protection
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into protecc-attester-db
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into protecc-attester-db
* Remove flags
* Add attestation history DB functions to validator client
* Fix comments
* Update interface to new funcs
* Merge branch 'master' of https://github.com/prysmaticlabs/Prysm into protecc-attester-db
* Fix test
* Merge branch 'master' into protecc-attester-db