ReadyNAS OS 6 Support

Main functionality for OS6 - Status, Log and Power screen have been
completed with a few caveats. 

1) users need to manually select their OS version up front
2) logs are showing the dictionary keys, rather than the user friendly
text

Additional cleanup and code refactoring is also still necessary. Need a
standard way for building Nml documents, and move all strings into xml.

#30