added english templates in the mail_template.yml (fixes #338)
added english templates in the mail_template.yml (fixes #338)

isaosano/OpenPNE3,ShinichiU/OpenPNE3,nise-nabe/ppcon-sns,ShinichiU/AuthFramework,isaosano/OpenPNE3,C-nakajima/OpenPNE3,nishizoe/OpenPNE3,openpne/OpenPNE3,ShinichiU/OpenPNE3,openpne/OpenPNE3,ShinichiU/OpenPNE3,ShinichiU/AuthFramework,nishizoe/OpenPNE3,ShinichiU/OpenPNE3,C-nakajima/OpenPNE3,isaosano/OpenPNE3,isaosano/OpenPNE3,upsilon/travis-test,C-nakajima/OpenPNE3,C-nakajima/OpenPNE3,openpne/OpenPNE3,kashiwasan/symfony-advanced,upsilon/travis-test,ShinichiU/AuthFramework,nise-nabe/ppcon-sns,tejima/OP3PKG,kashiwasan/symfony-advanced,tejima/OP3PKG,openpne/OpenPNE3