Multiple Fixes implemented

After deploying the plugin on my live site, I of course found multiple
bugs and issues. I've fixed what I've found so far, including but not
limited to:
- #25 - instead of creating sub-sub-sitemaps for each language(which
Google didn't like) all of the links to sitemaps are on the main index -
basically everything that's in the index for one-language site,
multiplied by the number of languages enabled
- #23 - Further improved the URL rewriting
- Better support for quicktags/translation shortcodes - now in widget
title/content and wp_title()