Insight - Flash crash charges garner increasing skepticism in high-speed world

By Douwe Miedema WASHINGTON (Reuters) - The notion that one man trading from his parents' house in a working class London suburb had a material role in the 2010 Wall Street flash crash has aroused increasing skepticism from investors and traders since charges were brought on Tuesday.     The U.S. has asked UK authorities to hand over Navinder Singh Sarao, 36, after his arrest this week on charges that he manipulated markets over several years in a fraudulent scheme that helped cause the