Here we are, one full decade -- 10 years, count 'em, one-10th of a century -- into the U.S. Army Corps of Engineers and City Of Dallas's Trinity River Corridor Project, and tomorrow the city council's Trinity River Corridor Project Committee has a briefing scheduled that I would summarize as, "The Corps of Engineers: Just What in the Hell Is That Thing, Anyway?"Ah, well. Better late than never.The briefing, scheduled for 11 a.m. in Room 6ES of City Hall, is actually titled "Overview of United St