This plugin uses libarchive to extend claws-mail's features to include
archiving of IMAP, LOCAL, and POP accounts as well as calendar accounts.

Archives are created with the following option:

    format
        - TAR
        - PAX
        - SHAR
        - CPIO

    compression:
        - GZIP/ZIP
        - BZIP2
        - None

    recursive
        - Yes/No