* cleanup of p2p design docs p2p implementation to match docs
  (mostly variable/function name/comment changes)
* fix bug in fetch_sync_items_loop() encountered if you
  disconnect from a client while requesting items
* add the ability to partition a network during testing by
  giving nodes a list of allowed peers to connect to.
* add a unit test to verify that basic synchronization
  works (when nodes are out of sync at startup, but
  no forks exist)