Make raycast benchmark default, to show improved raycasting performance.

Add rayTest to btBroadphaseInterface, and implement efficient version for btDbvtBroadphase to accelerate raycasting.
btAxisSweep3, btSimpleBroadphase and btMultiSapBroadphase implement brute-force method (as before). For now, it is recommended to use btDbvtBroadphase for fastest world raycast.

Demos/Benchmarks/main.cpp

@@ -26,13 +26,13 @@ int main(int argc,char** argv)
 {
 	GLDebugDrawer	gDebugDrawer;
 
-	BenchmarkDemo1 benchmarkDemo;
+//	BenchmarkDemo1 benchmarkDemo;
 //	BenchmarkDemo2 benchmarkDemo;
 //	BenchmarkDemo3 benchmarkDemo;
 //	BenchmarkDemo4 benchmarkDemo;
 //	BenchmarkDemo5 benchmarkDemo;
 //	BenchmarkDemo6 benchmarkDemo;
-//	BenchmarkDemo7 benchmarkDemo;
+	BenchmarkDemo7 benchmarkDemo;
 
 
 	benchmarkDemo.initPhysics();