Adding initial language menu support. Adding method lang_menu. Changing templates.

Link needs to be properly intergrated to the html href, translation
started earlier in sitemap and saved per language.
'en' special case as it is the original language of iso_639_3.xml

Updating templates with a Language menu item instead of a Level name
Levelname can be maintained in the template, translations are dynamic
as more pages in other languages gets created.

Problems will arrise when a language page is missing. This is first tests.. :)