Replace deprecated function is_site_admin()

is_site_admin() has been replaced by is_super_admin() in Buddypress 1.8 and higher.
Adding Swedish translation of English user-facing settings strings

These Swedish strings were originally hardcoded in templates/bp-forum-notifier-settings.php. I've added them to the language file and will replace them with the English strings in the template file.
Reflecting changes in the .po file.
Replaced Swedish strings and moved translation
Merge pull request #1 from hughtopping/patch-1

Replace deprecated function is_site_admin()
Merge pull request #2 from hughtopping/master

Replaced deprecated function is_site_admin() and updated language files