fixes #681 Speed up appveyor builds
fixes #681 Speed up appveyor builds

snikulov/nanomsg,thisco-de/nanomsg,featherweight/ftw-kernel-nanomsg,thisco-de/nanomsg,snikulov/nanomsg,reqshark/nanomsg,reqshark/nanomsg,featherweight/ftw-kernel-nanomsg,reqshark/nanomsg