By Marie-Louise Gumuchian LONDON (Reuters) – As the person who dressed the Sex Pistols, Vivienne Westwood, who died on Thursday at the age of 81, was synonymous with 1970s punk rock, a rebelliousness that remained the hallmark of an unapologetically political designer who became one of British fashion’s biggest names. “Vivienne Westwood died today, peacefully and surrounded by her family, in Clapham, South London. The world needs people like Vivienne to make a change for the better,” her fashion house said on Twitter. Climate change, pollution, and her support for WikiLeaks founder Julian Assa…