Stock index futures pointed to a lower open on Wall Street on Friday, adding to the two-week slump as investors continued to sell, spooked by the prospect of another recession. At 0900 GMT, futures for the S&P 500 down 0.48 percent, Dow Jones futures down 0.7 percent and Nasdaq 100 futures down 0.35 percent. Investors braced for the all-important U.S. monthly non-farm payrolls as well as the unemployment rate, due at 1230 GMT on Friday, seeking more insight on the extent of the damage in the labor market following a string of bleak macroeconomic data. Economists see payrolls up by...