support compound versus compound collision shape acceleration on GPU, using aabb tree versus aabb tree.

Remove constructor from b3Vector3,  to make it a POD type, so it can go into a union (and more compatible with OpenCL float4)
Use b3MakeVector3 instead of constructor
Share some code between C++ and GPU in a shared file: see b3TransformAabb2 in src/Bullet3Collision/BroadPhaseCollision/shared/b3Aabb.h
Improve PairBench a bit, show timings and #overlapping pairs.
Increase shadowmap default size to 8192x8192 (hope the GPU supports it)

src/Bullet3Common/b3Logging.cpp

@@ -18,22 +18,44 @@ subject to the following restrictions:
 #include <stdio.h>
 #include <stdarg.h>
 
+#ifdef _WIN32
+#include <Windows.h>
+#endif //_WIN32
+
 
 void b3PrintfFuncDefault(const char* msg)
 {
+#ifdef _WIN32
+	OutputDebugStringA(msg);
+#else
 	printf("%s",msg);
+#endif
+
 }
 
 void b3WarningMessageFuncDefault(const char* msg)
 {
+#ifdef _WIN32
+	OutputDebugStringA(msg);
+#else
 	printf("%s",msg);
+#endif
+
 }
 
+
 void b3ErrorMessageFuncDefault(const char* msg)
 {
+#ifdef _WIN32
+	OutputDebugStringA(msg);
+#else
 	printf("%s",msg);
+#endif
+    
 }
 
+
+
 static b3PrintfFunc* b3s_printfFunc = b3PrintfFuncDefault;
 static b3WarningMessageFunc* b3s_warningMessageFunc = b3WarningMessageFuncDefault;
 static b3ErrorMessageFunc* b3s_errorMessageFunc = b3ErrorMessageFuncDefault;