Fixed some stuff and made translation work!

myschoolday.sql

public/api/validate_token.php

public/css/calendar.css

public/css/style.css

public/functions/class.php

public/functions/html_stuff.php

public/index.php

public/locale/en/LC_MESSAGES/myschoolday.po

public/locale/myschoolday.pot

public/locale/nl/LC_MESSAGES/myschoolday.po

public/objects/school.php

public/objects/template.php

public/objects/user.php

public/templates/login.php

public/templates/logout.php

public/templates/manage_schools.php

public/templates/manage_users.php

public/templates/roster.php