Some internet feature requests

[massung]

1. Just as LOAD is an asynchronous GET, it would be nice to have an asynchronous POST.

2. The ability to cancel an asynchronous LOAD in progress (perhaps LOAD could put a handle in it that could be used to CANCEL the operation if it hasn't completed yet?). Similarly, canceling an asynchronous POST as well.

3. It would be nice if commands that take callbacks could also take some user data that could be forwarded to the callback as well. Right now we're stuck using static or global variables for what are often one-time operations.

Thanks!

Jeff M.