Add 1.9.1 section in NEWS file
Add 1.9.1 section in NEWS file

calvinmetcalf/CartoDB-SQL-API,CartoDB/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API,CartoDB/CartoDB-SQL-API