By Li-mei Hoang LONDON (Reuters) – Britain’s leading fashion brands are hoping to give menswear sales a lift by targeting younger, digitally savvy male shoppers with live streaming and social media to promote the twice-yearly mens fashion week that began on Friday. London is looking to establish itself as the leading menswear fashion capital over Paris, New York and Milan by dedicating four days to showcasing the latest trends – and designers and retailers are hoping to turn the catwalk buzz into cash. …