Ensure lucu namespace initialized
Refactored backup

Fixed bug where files were not being read (regression from earlier
changes). Inlined the code of importFeeds and deprecated the function.
Stopped using an IIFE. Deprecated the backup namespace, now uses global
IIFE namespace. Deprecated arrayValues function, the distinct feeds
array is now built in place using a simple statement, that code is now
functional instead of imperative.
Refactored onImportOPMLClick

Use new backup methods, inlined some functions, simplified the code and
made it more concise, cleaned up some comments, minor code style changes