Fix unified interface w/ editing multiple volumes

Fix unified interface w/ editing multiple volumes

Breakage if editing existing items across volumes with non-default values for
call number class, prefix, or suffix.  This was due to some logic happening
within a loop that was sadly referencing data that changed out from under it
with every loop iteration (so for example, we were effectively referencing the
last rendered class menu instead of each in turn).

Remember folks:

for (var unsafe = 0; unsafe < 10; unsafe++) {
    setTimeout(
        function(safe) {
            return function() {
                do_something_with(safe); // good
                do_something_with(unsafe); // bad
            };
        }(unsafe),
        1000
    );
}

Signed-off-by: Jason Etheridge <jason@esilibrary.com>