Bug 37369: Fix filtering of search result table in item search

Bug 37369: Fix filtering of search result table in item search

At the moment, the filtering on item results page
requires using the code in the following fields:
- Collection
- Home library
- Current library
- Shelving location
- Itemtype
- item status -fields (not for loan etc)

So e.g. "Centerville" in Home library -field doesn't
bring back results but code "CPL" does. This happens
because "columns" option in search results table
isn't working when its used in function columnFilter.
However option "aoColumns" works.

To test:
1. Navigate to item search and search items.
=> Note that all filters in search result table
are free text fields.
2. Attempt to filter search results by home library
with description of some library.
=> No results are displayed.
3. Now filter results with code of the library.
=> Results are now displayed.
4. Apply this patch and refresh page.
5. Search items again.
=> Note that now some of the filters are now using
dropdown select fields.
6. Attempt to filter results by home library again.
=> Results are now displayed correctly.

Sponsored-by: Koha-Suomi Oy
Signed-off-by: Olivier Hubert <olivier.hubert@inlibro.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>