LP#1862235 - Create MARC Record - focus on item add and call number

LP#1862235 - Create MARC Record - focus on item add and call number

This change sets the focus on the "Add Item" checkbox when the marc editor
is opened with fast item add enabled.  This allows the user to just press space
to enable Add item.

When the add item checkbox is enabled, the focus is moved to the call number field.

This adds a directive to app.js called focusOnShow that makes it easy
to mark an element to have focus when it becomes visible when using ng-show.

I had to add in a bit of redundancy in t_marcedit.tt2, the Add Item checkbox
needs to have it's own ng-show directive for the focus-on-show to work.

Signed-off-by: Josh Stompro <stompro@stompro.org>