By Cotten Timberlake, Bloomberg NewsWASHINGTON — With many Americans keeping a lid on spending, industry forecasters say the back-to-school season won’t be as strong as last year and are giving it a B- average. Once again, U.S. retailers are being forced to pour on the discounts because recent economic bright spots — more jobs, stronger growth — aren’t enough to persuade shoppers to spend freely.Read more on NewsOK.com