MEXICO CITY (Reuters) - Mexico will press ahead with oil investment and production plans, its energy minister told Reuters on Friday, arguing that a global crash in oil markets will be short lived and does not merit a change in strategy.In the coming days, the government will offer investment opportunities in more of its mature oil fields and network of refineries owned and operated by national oil company Petroleos Mexicanos (Pemex), Energy Minister Rocio Nahle said in an interview."Today we're..