LOS ANGELES, United States (AFP) — Pop superstar Katy Perry on Wednesday unleashed a worldwide scavenger hunt among her millions of online followers as she previewed a new song. In teasingly cryptic social media postings, the singer showed a video of a disco ball being dragged by a chain from her stiletto — recognizable from her foot tattoo of a grinning peppermint. Perry — the most popular person on Twitter with more than 95 million […]