Bug 8108 [Follow-up, revised] Remove unused OPAC images

Bug 8108 [Follow-up, revised] Remove unused OPAC images

This patch cleans up some loose ends:

- Star ratings images are now in one sprite. Removing
  separate star ratings images.
- Amazon ratings have been removed. Related image files
  are removed by this patch.
- The tag images associated with tag links on the search
  results page were not incorporated into the main sprite.
  Now they are.

Added: The Photoshop file from which the main sprite was
generated, in case that is helpful to others. Each layer
is named, and comments have been added to the CSS
referencing the layer names. The file is GIMP-compatible.

Revisions:
- Rebased on current master
- Ported some changes to CCSR theme
- Removed unused CSS which referred to deleted images

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Mason James <mtj@kohaaloha.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>