Removed some apparently unused properties in Importer and ImportManager

Signed-off-by: emanuele <emanuele45@gmail.com>
Default to an empty array if HTTP_ACCEPT_LANGUAGE is not set

Signed-off-by: emanuele <emanuele45@gmail.com>
Some tests for the Lang class

Signed-off-by: emanuele <emanuele45@gmail.com>