* 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
- Delete header on conflict to prompt data refresh (cascade deletes all
data associated with that block)
- Derive header hash from rpc payload rather than computing it from data
(prevents hash mismatch between blockchain and cache)
* Add shared test examples for repositories
- Create
- MissingHeaders
- MarkHeaderChecked
* Use shared repository tests for cat_file_chop_lump
* Use shared repository test for cat_file_flip
* Use shared repository test for cat_file_pit_vow
* Updates to shared repository tests
* Use shared repository tests for deal
* Small updates to repo tests
