By Belinda Goldsmith LONDON (Reuters) - British singer-songwriter Billy Bragg has mellowed over time, and the political activist is happy to focus more on struggles with relationships in his new album than political battles. Bragg, 55, made his name railing against Britain's right-wing government in the 1980s, a self-confessed angry young man who was spurred on by the miners' strike to use music to fight social injustice and then-Prime Minister Margaret Thatcher. ...