CheckChangeSets to work with plain state and changeSets, optionally generate receipts (#639)

* Start from 9m7

* Regenerate IH + receipts

* Only stats for iH bucket

* Persist receipts

* Go all in

* Start from block 10m

* Convert DbState to use plain state

* Fix findHistory

* Hard-code export

* More fixes

* Fix test

* Fix formatting

* Introduce PlainDbState

* Actually return PlainDbState

* Fix formatting

* Fix name style lint

* Fix linters

* Fix history_test

* Fix blockchain_test

* Fix compile error

* Bucket stats from all buckets