Restructure confmon a bit more

This restructures confmon to make its behavior more reliable and
testable.

More documentation has also been added to the header file to demonstrate
some aspects of the system

Change-Id: Ibff4d394808c21f2ef3c7463d8b543b415d46f95
Reviewed-on: http://review.couchbase.org/33825
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>