This changes the Blockchain to also return unpersisted (theoretically, verified
in the AddBlock!) blocks and transactions, making Add/Get interfaces
symmetrical. It allows to turn Persist into internal method again and makes it
possible to enable transaction check in GetBlock(), thus fixing #366.
earlier we had an issue with failing test in #353 and other one #305.
Reworked these test to have in-memory database. This led to multiple
changes: made some functions like Hash and Persist public(otherwise
it's not possible to control state of the blockchain); removed
unit_tests storage package which was used mainly for leveldb in unit
tests.
I see these tests not really good since they look like e2e tests and
as for me should be run in separate step against dockerized env or
in case we want to check rpc handler we might want to rework it in order
to have interface for proper unit tests.
As for me this patchset at least makes as safe with not removing totally
previous tests and at the same time CircleCI will be happy now.