fixed some outstanding issues with Bullet soft bodies:

1) re-allocate a pool allocator, if one of the soft body collision algorithms is larger than max pool element size
2) manage child shapes properly, and call RemoveReferences on the m_sparsesdf

src/LinearMath/btPoolAllocator.h

@@ -91,6 +91,11 @@ public:
         }
 	}
 
+	int	getElementSize() const
+	{
+		return m_elemSize;
+	}
+
 
 };