His muse is his at last! Twenty years after Quentin Tarantino directed Uma Thurman in Pulp Fiction, Us Weekly can confirm that the two have taken their relationship to the next level. Sources tell Us that the pair recently spent time together at the 2014 Cannes Film Festival in the South of France, where they even shared a villa. "They had a thing and got together again recently," one insider tells Us. "He's loved…