Support list_devices()

[mojca]

I have some proprietary (closed source) super slow C library for working with vxi11 and that one provides a function that returns all vxi11 devices at the network (and that's fast). This is the only function I miss in this python library.

Is there any chance to provide a search function in this library as well?

[alexforencich]

Give me a wireshark trace of what it does and I'll see about implementing it.

[alexforencich]

So, after some back-and-forth offline, it looks like the way this is done in general is with a broadcast UDP request to the portmapper service on the devices. Support for this already exists in rpc.py, so I put together an initial implementation of list_devices here:

https://github.com/alexforencich/python-vxi11/blob/af50c0ae5046c3ab6b6c7bd3dda03097e72577e6/vxi11/vxi11.py#L501

If all that looks good, then it's probably high time I bump the version.

[mojca]

See also https://github.com/mgmarino/VXI11Discovery