Celldex Therapeutics (CLDX) had its Relative Strength (RS) Rating upgraded from 61 to 72 Monday — a welcome improvement, but still short of the 80 or higher score you look for. When To Sell Stocks To Lock In Profits And Minimize Losses This exclusive rating from Investor's Business Daily tracks market leadership with a 1 (worst) to 99 (best) score.…