An IKC client is a session that initiates the connection. An IKC server is a
session that listens for new connections.  A given kernel can have both
client and server sessions.  Each kernel is it's own process.  This gets
confusing.  I tend to use remote and local kernel to designate which process
i'm talking about.

The client and server are nearly identical.  IKC is more of a peer-to-peer
protocol then a client/server protocol.  After negociation, either kernel
can send an event request to the other kernel.

Connection flow-chart (roughly) :

    IKC::Server                                 IKC::Client
        |                                            |
 Wheel::SocketFactory                                |
        |                                            |
        +--------------------------------------------+
        |
 (when connected)
        |
IKC::Channel::create_ikc_channel
        |
Wheel::ReadWrite (w/ Filter::Line)
        |
IKC::Channel does negociation
        |
Set filter to Filter::Reference
        |
create_ikc_responder()
        |
Register foreign kernels
        |
        +-------------------(IKC::Client) -----------+
        |                                            |
      Done                                on_connect sub ref called
                                                     |
                                                    Done


Data flow after Client <-> Server connection is established :

 Driver::SysRW      Driver::SysRW      Driver::SysRW      Driver::SysRW
      |                  |                  |                  |
Filter::Reference  Filter::Reference  Filter::Reference  Filter::Reference
      |                  |                  |                  |
Wheel::ReadWrite   Wheel::ReadWrite   Wheel::ReadWrite   Wheel::ReadWrite
      |                  |                  |                  |
IKC::Channel       IKC::Channel       IKC::Channel       IKC::Channel
      |                  |                  |                  |
      +------------------+--------+---------+------------------+
                                  |
                            IKC::Responder
                                  |
                          All other Sessions



Channel negociation

    Server               Client
    --<-- HELLO           --<--
    -->-- IAM KernelName1 -->--
    --<-- OK              --<--
    -->-- IAM OtherName1  -->--
    --<-- OK              --<--
     ....(more kernel names)....
    -->-- DONE            -->--

    --<-- IAM KernelName2 --<--
    -->-- OK              -->--
    --<-- IAM OtherName2  --<--
    -->-- OK              -->--
     ....(more kernel names)....
    --<-- DONE            --<--
    --<-- FREEZER XML::Storable --<--   
     ... negociating what type of reference serialisation we should use
    -->-- NOT             -->--
     .... server refused
    --<-- FREEZER Storable --<--
    -->-- OK              -->--
     .... server accepted
    --<-- WORLD           --<-- 
    -->-- UP              -->-- 

Negociation is now over and both sides switch to Filter::Reference.
NOTE : last message *has* to come from server