language autodetection: subsets like de-AT

[webograph <webograph@eml.cc>]

if someone comes to debian.org and has only his regional language-subset 
installed, but not the 2-letter-language (for example, de-AT and not 
de), the site is displayed in the default language - in english. since 
in most languages one text can be used for every language subset, i 
would suggest to instruct the language autodetection system to ignore 
this subset information.

webograph