move OpenCL initialization for the unit tests in a shared header file, and support some basic command-line arguments

--cl_device=1 --cl_platform=1 --allow_opencl_cpu
add chaindemo, test for mass ratios
restore sleeping/activation mode in featherstone demo
Use _VARIADIC_MAX=10 to avoid Google Test issues with Visual Studio 2012, thanks to Mobeen for the report
Enable verbose printf for unit tests

src/BulletDynamics/Featherstone/btMultiBody.h

@@ -418,6 +418,11 @@ public:
 		m_canSleep = canSleep;
 	}
 
+	bool getCanSleep()const
+	{
+		return m_canSleep;
+	}
+
     bool isAwake() const { return m_awake; }
     void wakeUp();
     void goToSleep();