Bug 17174: Making z39.50 Authority search actions buttons

Bug 17174: Making z39.50 Authority search actions buttons

Have changed the wording of the MARC button to Show MARC to be
consistent with other places in Koha.

To test:

1) Go to Authorities -> New from Z39.50
2) Put in any search terms and click Search
3) Confirm that both options (MARC and Import) now show as buttons "Show
MARC" and "Import" under one "Actions" column with approriate icons
4) Confirm buttons work as expected
5) Confirm buttons do not wrap on narrower browser

Sponsored-by: Catalyst IT
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>