Modularized uri.js, namespaced lucu

Created rewrite.js and fav-icon.js, moved logic out of uri.js, minor
comment improvements, added note about lucu namespace
Comment, whitespace cleanup
Moved getNodeValue to dom utils
Include fav-icon
Modularized string.js

Refactored string-utilities.js as string.js, updated dependencies,
modified comments
Added fav-icon

Forgot to add it to options.html after refactoring function out of
uri.js into its own file
Modularized opml