R&B superstar Usher released not one, but two new singles last week: "Crash" and "No Limit feat. Young Thug." "Crash" was co-written by Usher and produced by f a l l e n & Carlos St. John, and "No Limit feat. Young Thug" was co-written by Usher and produced by Brandon "B.A.M" Hodge and co-produced by Christopher…