allow several request to use single local storage

Signed-off-by: Sergei Ianovich <ynvich@gmail.com>
import Accept-Language hadling from i18n-abide

Signed-off-by: Sergei Ianovich <ynvich@gmail.com>
import Accept-Language test suite from i18n-abide

Signed-off-by: Sergei Ianovich <ynvich@gmail.com>