added cppunit unit testing framework, using cmake, stripped out the original build systems.

added starting point for Bullet unit tests, with one example unit test
Enable the option BUILD_UNIT_TESTS in cmake to build the test. Note that the test doesn't automatically run.

UnitTests/cppunit/include/cppunit/portability/CppUnitStack.h

@@ -0,0 +1,26 @@
+#ifndef CPPUNIT_PORTABILITY_CPPUNITSTACK_H
+#define CPPUNIT_PORTABILITY_CPPUNITSTACK_H
+
+// The technic used is similar to the wrapper of STLPort.
+ 
+#include <cppunit/Portability.h>
+#include <deque>
+#include <stack>
+
+
+#if CPPUNIT_STD_NEED_ALLOCATOR
+
+template<class T>
+class CppUnitStack : public std::stack<T
+                                      ,std::deque<T,CPPUNIT_STD_ALLOCATOR> >
+{
+public:
+};
+
+#else // CPPUNIT_STD_NEED_ALLOCATOR
+
+#define CppUnitStack std::stack
+
+#endif
+
+#endif // CPPUNIT_PORTABILITY_CPPUNITSTACK_H