archiver does not allow for attachment which is not multipart
archiver does not allow for attachment which is not multipart

This fixes #257
quenda/ponymail,quenda/ponymail,jimjag/ponymail,jimjag/ponymail,Humbedooh/ponymail,jimjag/ponymail,jimjag/ponymail,Humbedooh/ponymail,quenda/ponymail,Humbedooh/ponymail