[ENH] Adding LIST filter operator to filter elements containing spaces without having to add quites manually. {filter field=user identifier="john doe"}

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@51583 b456876b-0849-0410-b77d-98878d47e9d5
[ENH] Renaming to exact after a short reflection. {filter field=user exact="john doe"}

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@51584 b456876b-0849-0410-b77d-98878d47e9d5