Merge branch 'next'

* next: (31 commits)
  Code clarity improvements.
  Clean up variables and comments for run creation.
  Clean up run caching code in the Server class.
  Add a bit more compatibility info to the Readme.
  Document the Interaction Service additions in the README.
  Read notifications from the interaction feed.
  Add ratom and launchy gems to the runtime dependencies.
  Read interaction feed URI and query support with API.
  Make XPath searching robust to nodes not being found.
  Update copyright year in top-level Licence file.
  Add streaming examples to the README.
  Stream uploads of workflows and data.
  Add upload to streaming to the underlying connection.
  Expose stream-to-stream methods in the Run class.
  Add general stream-to-stream data downloads.
  Document the credentials classes.
  Remove deprecated files from the rdoc build.
  Stream output data directly to a file.
  Add output port data streaming functionality.
  Add methods to test for empty ports or port values.
  ...