Bug#183369: languagechooser: Should use kernel params if present

[Petter Reinholdtsen <pere@hungry.com>]

Package: languagechooser
Version: 0.13

The languagechooser should accept overrides as kernel parameters.  If
the LANG or LANGUAGE variable is passed to the kernel, they should be
used to set the locale (language/region) and list of langauge codes to
use.

For instance, LANG=nb_NO should make the installation use Norwegian
Bokmål locale by default, and LANGUAGE=nb:no:nn:da:sv should make it
use this list of languages in translations.