Bug 13339 - Cart button doesn't open the cart

Bug 13339 - Cart button doesn't open the cart

The link to open the cart no longer triggers the cart popup. Instead, in
order to make it more usable with mobile devices, it triggers a menu
which displays the count of items in the cart -- something which
previously was done with a hover action (something touch-screen devices
don't have). Clicking/tapping this menu item is what opens the cart
window.

Since the cart link is really now a menu trigger rather than just a
link, it seems logical to add the small arrow which the lists link
has indicating that the link triggers a menu.

To test, apply the patch and view any page in a Cart-enabled OPAC.
Confirm that the "caret" icon displays correctly when the cart is both
empty and when it has contents.

Followed test plan. Icon displays as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Works as described, good idea.
Signed-off-by: Mason James <mtj@kohaaloha.com>