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)

build3/premake4.lua

@@ -227,6 +227,7 @@
 			include "../test/gtest-1.7.0"
 --			include "../test/hello_gtest"
 			include "../test/collision"
+			include "../test/BulletDynamics/pendulum"
 			if not _OPTIONS["no-bullet3"] then
 				if not _OPTIONS["no-extras"] then
 					include "../test/InverseDynamics"