It's not just your imagination: St. Louis houses really are flying off the MLS system almost as fast as agents can list them. In fact, 31 percent more single family homes were sold in the St. Louis area in November 2016 than in the prior year, according to the organization St. Louis REALTORS.The area's median sales price also rose ten percent from November 2015 to November 2016 — with the median home now selling for $164,500, an increase of $14,500.…