(Adds acronym of rebel group that took control of Laukkai town in paragraph 6) (Reuters) -An ethnic armed group in the western Myanmar state of Rakhine said it has taken control of a town bordering India and Bangladesh, marking the latest loss for the military government as it battles rebellion in several parts of the country. Myanmar is in the throes of an insurgency on multiple fronts, where allied anti-junta groups backed by a pro-democracy parallel government have seized control of several military posts and towns. It is the biggest challenge the junta has faced since it mounted a coup aga…