TelePharo in Tonel

It requires finally merging branch with network discovery tool. Otherwise it would be a pain to do it after conversion.

The branch provides a Radar tool to discover available images in the network. Generally it works but it needs real live testing. Some logic of server connection was refactored to achieve it and it needs real tests.

Also it adds new dependency to SSDP library which is currently managed by smalltalkhub. It would be nice to move it into github. But it needs to be in sync with the author (Henrik Johansen).