* Upgrade geth from 1.8.15 to 1.8.18
* Update vat_tune to use shared repository methods
* Query blockchain by block hash instead of block number range
* Remove hash validation from repositories
* Fix vow flog integration test
* Update README Travis build sticker
* Update constants formatting per go fmt
* Update EthPublicKeyParser.ParsePublicKey to use discv5.PubkeyID method
* Address PR comments
= Add eth_node_fingerprint to block that can be imitated by both hot and cold imports
- Only sync missing blocks (blocks that are missing or don't share a fingerprint) on cold import
- Set block is_final status after import