Don't delete the index as it causes some issues with the cluster not being ready for the query
Removed config property as it's not used in any of the transport implementations
Removed _path, _method and _data as these are not used by any transport,
and added a create method that can be used as a factory for transports.
Also added a test case for the factory.
Make the Connection class use the transport factory
Updated changes.txt with information regarding the transport factory
Make the connection instance optional as the transport factory uses the setConnection method to set the connection instance when creating transports
Fetch the param from the transport instance and not the connection instance
Merge pull request #326 from christeredvartsen/transport-factory

Transport factory