Arm miknode with the tools to handle commands.

* Modify miklist's close to correctly free packets of commands and events.
* Add function headers for miklist and mikpeer functions to miknet for miknode.
* Implement send function for peers, which queues a packet for sending when the
  node is allowed to loop.
Fix cleaning up miknode structures.
Add new peers to the node's poll list.
Prevent accessing unclaimed memory when closing miklists and nodes.
Draft connecting peers.

This is the first implementation of connecting two peers on the decentralized
branch (mono).