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

test/gtest-1.7.0/premake4.lua

@@ -5,6 +5,10 @@
 	files{"src/gtest-all.cc"}
 
 	--defines {"GTEST_HAS_PTHREAD=1"}	
+	
+	--see http://stackoverflow.com/questions/12558327/google-test-in-visual-studio-2012
+	defines {"_VARIADIC_MAX=10"}	
+	
 	--targetdir "../../lib"	
 
 	includedirs {