REST API changes to make it easier to interact with brooklyn api

First commit splits the former 'brooklyn-rest' into 'brooklyn-rest-api' and 'brooklyn-rest-server', The second adds an example client interface ('brooklyn-rest-client' using resteasy). The inclusion (or not) of the second commit isn't overly important - I can add 'brooklyn-rest-client' in sandbox or examples if this is preferred.

NOTE: we've got a few non-standard bits and pieces in the api which are forcing inclusion of some Jersey 1.x dependencies (e.g. the multipart form data annotations in CatalogApi). But overall this change is moving us in the right direction!