adding tabular output to swauth-list

swauth-list now shows lists of accounts, users and groups
in a tabular format (default). JSON and plain-text options
are still available

Change-Id: I897009f5f6c05aa4c14e306bb6ad35234e993fcd
Signed-off-by: Thiago da Silva <thiago@redhat.com>
Reviewed-on: http://review.gluster.org/6347
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>
Reviewed-on: http://review.gluster.org/6372