TODO handshake for NodeLink to first check protocol versions

* master: (23 commits)
  Make the identification of the primary master easier with 'neoctl print node'
  client: fix AttributeError when connected to a master that happens to be secondary
  qa: speed up SQlite tests by accessing DBs in unsafe mode (e.g. no sync)
  master: fix identification of unknown masters
  Better logging of connector errors
  qa: relax assertion in testDeadlockAvoidanceBeforeInvolvingAnotherNode
  client: fix possible data corruption after conflict resolutions with replicas
  qa: new --readable-tid runner option
  qa: make Patch work on functions
  qa: new --continue-on-success and --stop-on-success runner options
  doc: add advice about the number of master nodes to set up
  Improvements to --dynamic-master-list
  Make NodeManager.remove stricter
  Clean up neo.lib.protocol
  Use ProtocolError instead of Notify for unexpected answers, and drop Notify
  Rename node states: DOWN -> UNKNOWN, TEMPORARILY_DOWN -> DOWN
  Remove UNKNOWN node state
  Reimplement election (of the primary master)
  Use existing generic way to ignore AcceptIdentification on closed connections
  Remove BROKEN node state
  ...

Now, the primary master is the running master with None displayed in the
last column. Before, it could be the id timestamp of when it was secondary,
which was obsolete information.