Compatibility with OpenSearchServer v1.5 (dev3)

This new version is based on the new RESTFull of OpenSearchServer v1.5.
All methods are using JSON. All URL construction are simpler. New tests has been added.
This version requires at least OpenSearchServer v1.5-dev3  available here:
http://www.open-search-server.com/ftp/OpenSearchServer_1.5/build-1.5-dev3-b232/