add a Pendulum example that is also used as unit test.

Gold data is created by numerically solving a second-order non-linear differential equation.
(see examples/MultiBody/pendulum_gold.h)

test/BulletDynamics/pendulum/premake4.lua

@@ -0,0 +1,34 @@
+
+	project "Test_BulletDynamics"
+		
+	kind "ConsoleApp"
+	
+	defines {"USE_GTEST"}
+	
+
+	
+	includedirs 
+	{
+		".",
+		"../../../src",
+		"../../gtest-1.7.0/include"
+	
+	}
+
+
+	if os.is("Windows") then
+		--see http://stackoverflow.com/questions/12558327/google-test-in-visual-studio-2012
+		defines {"_VARIADIC_MAX=10"}
+	end
+	
+	links {"BulletDynamics", "BulletCollision","LinearMath", "gtest"}
+	
+	files {
+		"../../../examples/MultiBody/Pendulum.cpp",
+		"../../../examples/MultiBody/pendulum_gold.h",
+	}
+
+	if os.is("Linux") then
+                links {"pthread"}
+        end
+