update/unify license headers

appinfo/app.php

appinfo/register_command.php

appinfo/routes.php

lib/account.php

lib/attachment.php

lib/cache/cache.php

lib/command/createaccount.php

lib/controller/accountscontroller.php

lib/controller/autocompletecontroller.php

lib/controller/folderscontroller.php

lib/controller/messagescontroller.php

lib/db/collectedaddress.php

lib/db/collectedaddressmapper.php

lib/db/mailaccount.php

lib/db/mailaccountmapper.php

lib/hordetranslationhandler.php

lib/http/attachmentdownloadresponse.php

lib/http/htmlresponse.php

lib/http/proxydownloadresponse.php

lib/mailbox.php