more memory leak fixes in demo and btSimpleBroadphase.

- deleting object (END key) needs to release
- call destructor of pair cache

src/BulletCollision/BroadphaseCollision/btSimpleBroadphase.cpp

@@ -77,6 +77,7 @@ btSimpleBroadphase::~btSimpleBroadphase()
 
 	if (m_ownsPairCache)
 	{
+		m_pairCache->~btOverlappingPairCache();
 		btAlignedFree(m_pairCache);
 	}
 }