API extension: allow to set comments inside network interfaces file
vzdump: add MIME-Version header

Some clients need this to correctly interpret multipart messages.
bump version to 3.1-42
bump version to 3.1-43 (fix network API)
bump version to 3.1-44, re-add spiceconfig support
Merge branch 'master' of git://git.proxmox.com/git/pve-manager