Stocks ran out the clock Friday, posting small gains in a productive week for the bulls. The Nasdaq and the S&P 500 added 0.4% and 0.1%, respectively. The IBD 50 rose 0.5%. Volume fell across the board. The S&P 500 did its part for the bulls, retaking its 50-day moving average Thursday and holding above it Friday. The Nasdaq sent a mixed signal: It finished below its 50-day moving average but above its 10-week line.