* Add VirtualBlueHashes to BlockDAG
* Refactor TestGHOSTDAG to read DAGs from json files
* Added a new DAG for the ghostdag test suite
* Pass BehaviorFlags to delayed blocks
* [NOD-1223] Delete unused files/packages.
* [NOD-1223] Move signal and limits to the os package.
* [NOD-1223] Put database and dbaccess into the db package.
* [NOD-1223] Fold the logs package into the logger package.
* [NOD-1223] Rename domainmessage to appmessage.
* [NOD-1223] Rename to/from DomainMessage to AppMessage.
* [NOD-1223] Move appmessage to the app packge.
* [NOD-1223] Move protocol to the app packge.
* [NOD-1223] Move the network package to the infrastructure packge.
* [NOD-1223] Rename cmd to executables.
* [NOD-1223] Fix go.doc in the logger package.
* [NOD-1223] Move all network stuff into a new network package.
* [NOD-1223] Delete the unused package testutil.
* [NOD-1223] Move infrastructure stuff into a new instrastructure package.
* [NOD-1223] Move domain stuff into a new domain package.
