ElabinElab changes:

* sslxmlrpc_server.py: A rather gross hack that needs more thought;
  pass the client IP address to the emulabserver class instantiation,
  which is passed along to the new elabinelab module ...

* emulabserver.py: A new class called elabinelab which exports some methods
  that are to be used by an inner elab. At present, the IP address of the
  client is passed along and a bunch of checks are made that restrict the
  client to the inner emulab boss node, with the credentials of the
  creator of the inner emulab. In other words, the ssl certificate of the
  elabinelab creator is placed on the inner boss, and all proxy
  operations are invoked with this certificate (as the creator) and
  only from the inner boss node.

  The elabinelab class currently exports two methods; a power method
  to power cycle an inner node; the command is handed of the power
  command, which does the permission checks. Of course, the inner boss
  does its permission checks, but ultimately, the outer boss will
  allow the power cycle only if the client is allowed to power cycle the
  node.

  The other method exported is a vlans command to setup and destroy a
  set of vlans for an inner experiment. Permissions checks are modeled as
  above, with everything passed out to new snmpit.proxy script, which
  then invokes plain snmpit.