Bug 18499: Use items cn_source in cn_browser.pl

Bug 18499: Use items cn_source in cn_browser.pl

This does a few things:
 * We fetch the cn_sort from the DB and use this rather than calculating based on DefaultClassificationSource
   We were already pulling based on the items source, so this should not change things
 * Rather than using JS to submit the form, it submits via html
 * Fix subtitle display and add barcode (it was retrieved in one query but not used)
 * Add option to apply different classification scheme to the search

To test:
 1 - Add cn_browser.pl to the 'plugin' field in a framework for 952$o
 2 - Edit an item on a record in that framework
 3 - Enter an itemcallnumber
 4 - Click the two dots to launch the callnumber browser
 5 - Note the results
 6 - Apply patch
 7 - Repeat
 8 - Note subtitles and barcodes are displayed in results
 9 - Note callnumbers are appropriate
10 - Try changing the class source used
11 - Try this with differing dewey,lcc, and other callnumbers
12 - Ensure results are as expected

Signed-off-by: Myka Kennedy Stephens <mkstephens@lancasterseminary.edu>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>