automatic language selection, based on Accept-Language HTTP header

lib/AccountManager/WebRequest.pm

templates/Makefile.am

templates/web/en/complete_challenge.tt2.html

templates/web/en/content.tt2.html

templates/web/en/create_accounts.tt2.html

templates/web/en/errors.tt2.html

templates/web/en/home.tt2.html

templates/web/en/index-nobanner.tt2.html

templates/web/en/index.tt2.html

templates/web/en/notices.tt2.html

templates/web/en/select_email.tt2.html

templates/web/en/select_sp.tt2.html

templates/web/fr/complete_challenge.tt2.html

templates/web/fr/content.tt2.html

templates/web/fr/create_accounts.tt2.html

templates/web/fr/errors.tt2.html

templates/web/fr/home.tt2.html

templates/web/fr/index-nobanner.tt2.html

templates/web/fr/index.tt2.html

templates/web/fr/notices.tt2.html