Add in limited admin packet support with testcase improvments.

This is not a fully completed update, but with a pressing
bug in progress, the first round of commits is fine.  The
API will be revised once the functionality is complete.
Provide better re-entrant behaviour for io_service exception.

Change some of the data handling to prevent potential out of
bounds iteration; Change metaserver timer initialisation to be
discrete so that it can be done properly in the event of an
exception, allowing for self-recovery; tests and revision
bump to handle changes and tests.
http://bugs.launchpad.net/metaserver-ng/+bug/1220859