Update the MemoryManager API so it can be used in conjunction with NIO to provide efficient buffer management

If MemoryManager implemented something like a ByteBuffer allocate(int size) then I could be used to directly transfer data to/from Files and Sockets without having to first copy them to a byte[].

I'm not talking about using the ByteBuffer.allocate call. I'm talking about adding a method to MemoryManager:

ByteBuffer bb = MemoryManager.allocate(1024*1024);
So that I can directly modify the ByteBuffer using Channels to avoid a memory copy.. Compare this to using the MemoryManager store, update, and retrieve calls. They all force you to work with byte[]s so you end up doing a memory copies into and out of direct memory.

This was originally reported at: https://github.com/raffaeleguidi/DirectMemory/issues/49#issuecomment-2661141