Bug 11002: (follow-up) use jQuery validator plugin

This patch uses the jQuery validator plugin introduced in
bug 6209 for two reasons:

[1] To supply validation for non-HTML5-compatible web
    browsers.
[2] To force use of the validator plugin rather than
    built-in validation for HTML5 browsers, which means
    that our translations will be used.

Note that a version of the function to prevent double form submission
is used as the submit handler invoked when the validator plugin
is satisified that the form is complete.

To test:

[1] Same as the main test plan, but note that the validation
    messages now appear inline rather than as pop-ups.
[2] Verify that the double form submission prevention still
    works.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit e52bd72c65)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>

koha-tmpl/intranet-tmpl/prog/en/modules/members/memberentrygen.tt

@@ -33,7 +33,16 @@
             }
         [% END %]
         $("#dateofbirth").datepicker({ maxDate: "-1D" });
-        $("#entryform").preventDoubleFormSubmit();
+        $("#entryform").validate({
+            submitHandler: function(form) {
+                $("body, form input[type='submit'], form button[type='submit'], form a").addClass('waiting');
+                if (form.beenSubmitted)
+                    return false;
+                else
+                    form.beenSubmitted = true;
+                    form.submit();
+                }
+        });
     });
 
     function clear_entry(node) {