By Scott Malone and Edward McAllister FERGUSON Mo. (Reuters) - Missouri's governor ordered National Guard troops to withdraw from the riot-weary town of Ferguson on Thursday as tensions eased after nearly two weeks of racially charged protests over the fatal police shooting of an unarmed black teenager. Demonstrators were orderly for a second straight evening on Thursday, the calmest night in the St. Louis suburb since 18-year-old Michael Brown was gunned down by a white police officer on Aug. 9 under disputed circumstances. Keep them close." Ferguson erupted in anger after the teenager's slaying, with nightly rallies frequently punctuated by looting, vandalism and clashes between protesters and heavily armed riot police, often ending in volleys of tear gas and dozens of arrests.