LP#1785061: Split filter value on comma for "in list" and the like

LP#1785061: Split filter value on comma for "in list" and the like

This commit borrows directly from the XUL reporter code (see
function __default_value_event_handler () in
Open-ILS/web/reports/xul/template-config.js). Basically, when the filter
value is saved, certain cases need special treatment, such as splitting
an "in list" value on commas. This commit includes a helper function
which does the special treatment and saves the filter value. This helper
is called both when the value itself is changed, and when the operator
is changed.

Signed-off-by: Remington Steed <rjs7@calvin.edu>