fix memory leak in BulletMultiThreaded

Fixes Issue 271.

src/BulletMultiThreaded/PosixThreadSupport.cpp

@@ -248,6 +248,9 @@ void PosixThreadSupport::stopSPU()
             destroySem(spuStatus.startSemaphore);
             printf("semaphore destroyed\n");
 		checkPThreadFunction(pthread_join(spuStatus.thread,0));
+
+		if(spuStatus.m_lsMemory)
+			delete spuStatus.m_lsMemory;
         }
 	printf("destroy main semaphore\n");
         destroySem(mainSemaphore);

src/BulletMultiThreaded/Win32ThreadSupport.cpp

@@ -299,6 +299,9 @@ void Win32ThreadSupport::stopSPU()
 		CloseHandle(spuStatus.m_eventCompletetHandle);
 		CloseHandle(spuStatus.m_eventStartHandle);
 		CloseHandle(spuStatus.m_threadHandle);
+
+		if(spuStatus.m_lsMemory)
+			delete spuStatus.m_lsMemory;
 	}
 
 	m_activeSpuStatus.clear();

src/BulletMultiThreaded/btParallelConstraintSolver.cpp

@@ -1157,6 +1157,8 @@ btParallelConstraintSolver::~btParallelConstraintSolver()
 {
 	delete m_memoryCache;
 	delete m_solverIO;
+	delete m_barrier;
+	delete m_criticalSection;
 }