Updated the language files to fix issue #U4-3979

Also corrected invalid URL's across all the language files as they pointed to pages on Umbraco.com/org that 404'ed.
Hi,

I have updated all the files to use the same link:

    <name>The Umbraco community</name>
    <link>http://our.umbraco.org</link>

As these files are obviously a community effort it seems to make sense that it should be the community site URL. Ideally linking to a page talking about the Language files, but as one currently does not exist in the new documentation section, the root URL is probably best for now.