Bug 19461: Add floating toolbar to staff client catalog search results

Bug 19461: Add floating toolbar to staff client catalog search results

This patch adds a floating toolbar to the staff client search results
page, making all the various controls visible as the user scrolls down.

To test, apply the patch and perform a catalog search in the staff
client.

- The toolbar should "stick" to the top of the page as you scroll down.
- Controls in the toolbar should all work correctly:

  - Select all / Clear all
  - Highlight / Unhighlight
  - Add to Cart
    - Cart notifications should be positioned correctly
  - Add to list (and all list menu controls)
  - Place hold (including controls which are visible when
    a "Search to hold" has been initiated
  - Z39.50/SRU search
  - Sort

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>