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
  ...