Make BenchmarkDemo a console application, without OpenGL/Glut dependency.

Fix potential division by zero when enabling convex distance utility.
Thanks to linzner http://code.google.com/p/bullet/issues/detail?id=264

Demos/Benchmarks/Jamfile

@@ -1,3 +1,3 @@
 SubDir TOP Demos Benchmarks ;
 
-BulletDemo Benchmarks : [ Wildcard *.h *.cpp  ] ;
+BulletBasicDemo Benchmarks : [ Wildcard *.h *.cpp  ] ;