Add range-mod command
    
    range plugin was missing range-mod command that could be used for
    example to fix a size for a range generated during upgrades. The
    range should be updated with a caution though, a misconfiguration
    could break trusts.
    
    iparangetype is now also handled better and filled in all commands
    instead of just range-show. objectclass attribute is deleted only
    when really needed now.