Add ZEO to a grokproject buildout

It took some time today to get the docs together and setup a ZEO Server and Client configuration for an existing grokproject buildout.

The story so far...

• In the [buildout] section add zodb, server and instance2 for the ZODB, the ZEO server and a second instance.
• the [zodb] section is just defining the egg.
• the [server] section configures the ZEO server port address (at localhost) and the type of the ZODB storage. The <runner> configuration is created by the recipe in parts/server/zdaemon.conf by default.
• the [zopectl] section is modified to a ZEOClient
• the [instance2] section defines another ZEOClient, it 'extends' the existing [zopectl] instance and configures a different port address (default is 8080).

--- buildout.cfg ---
[buildout]
...
parts = ... zodb server instance2
...
[zodb]
recipe = zc.recipe.egg:script
eggs = ZODB3
[server]
recipe = zc.zodbrecipes:server
zeo.conf =
   <zeo>
      address 8100
   </zeo>
   <filestorage 1>
      path /absolute/path/to/ZEOData.fs
   </filestorage>
[zopectl]
recipe = zc.zope3recipes:instance
application = app
zope.conf =
    <zodb>
      <zeoclient>
        server 127.0.0.1:8100
      </zeoclient>
    </zodb>
[instance2]
recipe = zc.zope3recipes:instance
extends = zopectl
address = 9080
...

bin/server and bin/instance2 are the two new scripts created to control the ZEO server and the second client (start, stop, restart). It works for me, let me know if there is anything missing.