If you’re looking for warning signs that the stock market is due for drop, retail investors convinced of their own prowess is a good one. But even day traders keep with the times, and according to Fidelity’s Mobile Money Study more and more of them are trading on mobile apps, which they believe gives them some sort of edge over the competition. “The growing momentum for mobile trading use is not only a matter of added convenience, but one of added confidence, too,” says the study. “For example, 69 percent of those who trade with their mobile apps say they…