* 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)
* Move chop lump transformer test to a generic log_note_transformer_test
* Add test cases to transformer test
- cat file flip
- cat file pit vow
- deal
- dent
* Move transformer tests over to transformer factor test file
- drip drip
- drip file ilk/repo/vow
- pit file deb ceiling/ilk/stability fee
- price feeds
* Move LogNoteTransformer test into factory package and remove log specific transformer tests
* Move Transformer test into factory package and remove log event specific transformer tests
* Respond to PR comments
* Use transformer factory for Bite
- introduces separate transformer factory for non-LogNote events
- converter includes `ToEntities` for events defined via ABI
* Updates after rebasing with staging
* Log checked headers for Bite events
* Log checked headers for Drip drip events
* Log checked headers for Drip file events
- mark headers checked for 3 implementations of file on the Drip contract
* Log checked headers for Frob frob events
* Log checked headers for Pit file events
- mark headers checked for 3 implementations of file on the Pit contract
* Log checked headers for Vat init events
