Bug 16576 [Revised] Remove the use of "onclick" from label templates

Bug 16576 [Revised] Remove the use of "onclick" from label templates

This patch updates several label creator templates to remove the use of
"onclick" in favor of defining click events in JavaScript.

Also changed:
 - Replaced the non-existant element <icon> with <i>
 - Removed the use of <center> and 'align="center"';
 - In the item search results template:
   - The use of the checkboxes jQuery plugin has been replaced with
     straight jQuery for simplicity's sake.
   - Output of table headers has been modified so that translatable
     strings are in the template instead of having English strings
     passed from the script.
   - Moved the 'Add checked' and 'Done' buttons into a floating toolbar.

To test, apply the patch and go to Tools -> Label creator.

- Choose New -> Label batch
  - Click 'Add items'
    - Perform a search for items.
    - Confirm that 'select all' and 'clear all' links work.
    - Confirm that clicking an individual 'Add' button works.
    - Select multiple items and click the 'Add checked' button. Confirm
      that the selected items were added to your batch.
  - Click 'Add items' again to save the selected items to your batch.
  - Test that the 'Delete' and 'Export' buttons next to any item work
    correctly.
- Choose Manage -> Label batches
  - Test that the 'Delete' button works correctly.
  - Select one or more batches and test that the 'Export selected'
    button works correctly.

Revision: Removed changes to pagination in the item search results
template since it didn't work.

Followed test plan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>