LAS VEGAS, NV-  First-round draft choice MarJon Beaumchamp started the N-B-A Summer League games with a solid performance Friday night.  He hit three-of-six 3-pointers while scoring 16 points, but it was the defensive performance by the six-foot-seven forward that caught everyone’s attention.  Sandro Mamukelashvili and Lindell Wigginton led the Bucks with 17 points as they edged Brooklyn 94-90.  Milwaukee hit 17-of-33 3-pointers.  The team meets Boston Monday.