* [NOD-1496] Implement headers only verification
* [NOD-1496] Add checkParentsExist
* [NOD-1496] Stage block statuses in block processor
* [NOD-1496] Rename AddBlock->AddHeaderTip
* [NOD-1496] Return early from validateAndInsertBlock on header only and put ValidateProofOfWorkAndDifficulty inside validateBlock
* Add new ErrMissingTxOut error
* Add tests for ruleError wrapping
* Update consensus to use new ErrMissingTxOut type where appropriate
* Add new ErrInvalidTransactionsInNewBlock error
* Add wrapping tests for ErrInvalidTransactionsInNewBlock
* Fix Review suggestions
* Fix broken serialization(add pointer redirection)