fixed #855

simplified trace from functions, removed clippy warnings

Update deprecated HashDB methods in docs.

refactored loading transaction json tests

reorganised price info lookup

This helped stop my eyes from hurting.

Further simplification

Publish locally-made transactions to peers.

Add generalbeck's token

Fix response for mining.

USD-based pricing of gas.

Parity can accept older work packages

Caching for computing seed hashes (#541)

Code review changes

`ClosedBlock`s still keep the pre-finalised state (i.e. state after the last transaction).
`LockedBlock`s do not. New mining algo needs to reopen these `ClosedBlock`s, however enactment
system does not (and `ClosedBlock`s are slower & more hungry), hence the distinction.

checking transaction queue for pending transaction

refactored loading of state tests

tests for deserialization of transaction from issue #835

unlocks with no expiration [on top of 833]