Commit related to issue 
https://opends.dev.java.net/issues/show_bug.cgi?id=1334

This commit implements the underlying actions for the following subcommand:

     add-to-group      Add a member to a group
     create-group      Create a new group of servers
     delete-group      Delete an existing new group of servers
     list-groups       List groups that have been defined
     list-members      List members of the specified group
     list-membership   List members of the specified group
     modify-group      Modify a group's properties
     remove-from-group Remove a member from a group

Error handling and user friendly outputs are not part of this commit.