update default port. the http client does not follow redirects for PUT or DELETE, so we can't rely on it.
add missing management http api functions
RabbitMQ expects all request to also have a declared content type of
fix test-list-bindings (ensure the referenced exchange and queue exist)
add tests for vhost/user/permissions manipulation functions of the http management api
Merge pull request #23 from smee/master

Add more functions to the http management api