Bug 11765 - Remove unused function isDate from templates

Bug 11765 - Remove unused function isDate from templates

Several administration templates declare but do not use the JavaScript
function isDate(). This patch removes the declarations.

To test, apply the patch and search for instances of "isDate" in Koha
templates, includes, and JavaScript files. There should be no results.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
I'm not sure this function has ever been used.
This patch removes the toUC in tools/letter.tt too.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>