Add --enable-maintainer-mode

Maintainer mode enables --enable-werror --enable-warnings
--enable-debug, forces all plugins to be installed and forces all tests,
tools, and examples to be built

Change-Id: I2de15559f02ab453b6aeb3075ed2a131baee1617
Reviewed-on: http://review.couchbase.org/29767
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>