Move some code from Branches/OpenCL to trunk, related to threading and OpenCL:

Added Demos/ThreadingDemo showing how to use the cross-platform btThreadSupportInterface under Windows.
Added Demos/ParticlesOpenCL showing how to run the NVidia particle demo under OpenCL implementations by AMD, NVidia and MiniCL (CPU)

Demos/ThreadingDemo/CMakeLists.txt

@@ -0,0 +1,45 @@
+# This is basically the overall name of the project in Visual Studio this is the name of the Solution File
+
+
+# For every executable you have with a main method you should have an add_executable line below.
+# For every add executable line you should list every .cpp and .h file you have associated with that executable.  
+
+
+# This is the variable for Windows.  I use this to define the root of my directory structure.
+SET(GLUT_ROOT ${BULLET_PHYSICS_SOURCE_DIR}/Glut)
+
+# You shouldn't have to modify anything below this line 
+########################################################
+
+#currently this demo has only been tested under Windows 32bit
+IF (WIN32)
+
+INCLUDE_DIRECTORIES(
+	${BULLET_PHYSICS_SOURCE_DIR}/src ${BULLET_PHYSICS_SOURCE_DIR}/Demos/OpenGL 
+	${VECTOR_MATH_INCLUDE}
+)
+
+IF (USE_GLUT)
+	LINK_LIBRARIES(
+	OpenGLSupport  BulletMultiThreaded BulletDynamics  BulletCollision LinearMath  ${GLUT_glut_LIBRARY} ${OPENGL_gl_LIBRARY} ${OPENGL_glu_LIBRARY}
+	)
+
+	IF (WIN32)
+	ADD_EXECUTABLE(AppThreadingDemo
+			main.cpp
+			${BULLET_PHYSICS_SOURCE_DIR}/msvc/bullet.rc
+		)
+	ELSE()
+		ADD_EXECUTABLE(AppThreadingDemo
+			main.cpp
+		)
+	ENDIF()
+ENDIF (USE_GLUT)
+
+IF (INTERNAL_ADD_POSTFIX_EXECUTABLE_NAMES)
+			SET_TARGET_PROPERTIES(AppThreadingDemo PROPERTIES  DEBUG_POSTFIX "_Debug")
+			SET_TARGET_PROPERTIES(AppThreadingDemo PROPERTIES  MINSIZEREL_POSTFIX "_MinsizeRel")
+			SET_TARGET_PROPERTIES(AppThreadingDemo PROPERTIES  RELWITHDEBINFO_POSTFIX "_RelWithDebugInfo")
+ENDIF(INTERNAL_ADD_POSTFIX_EXECUTABLE_NAMES)
+
+ENDIF(WIN32)