Defines a block allocator that allocates and deallocates memory blocks of a single size.
The cache_freelist template class maintains a free list of memory blocks of size Sz. When the free list is full it uses operator delete to deallocate memory blocks. When the free list is empty it uses operator new to allocate new memory blocks. The maximum size of the free list is determined by the class max class passed in the Max parameter.
Each memory block holds Sz bytes of usable memory and the data that operator new and operator delete require.