In-progress updates to RUIH service based on patch feedback, with additional changes.
 - Logic in UIListingManager moved, class deleted
 - Updated location of UIList.xml to $HOME/.config/Rygel/UIList.xml
 - Removed logic which created temporary files, passing data in memory as needed
 - Moved RuihServiceError to Ruih service manager, using spec-defined codes and returning those codes in the action where appropriate.
 - Removed members including static members where possible
 - Updated parsing logic to ignore TEXT nodes
 - Replaced string-based error passing with throwing of RuiServiceErrors
 - Removed XMLFragment internal class which held members which needed to be represented as XML, now using a to_XML helper method to generate the XML.
 - Replaced generic GLib.Error throws with RuihServiceError throws
 - Replaced if-blocks with switch/case statements in XML node walking logic
 - Using early returns where possible

Outstanding tasks:
 - Extract inner classes to top-level classes
 - Concurrency handling (UIList updates and queries)
 - White space and code convention updates