Fix crash when parsing ACCEPT_LANGUAGE

If the value of the header ACCEPT_LANGUAGE is not in the expected format the code would crash. By wrapping it inside a begin-rescue we can handle these cases and let the language detector move on.
Fix whitespace for alignment

Made some lines follow the code style by converting tabs into spaces when they are used for alignment and not indentation.
Fix link to duplicate version

The link to Stoffi on Software Informer was to a version they have marked as a duplicate. Change the link so it points to the "master" version.