orange3

As suggested in biolab/orange3#2793 (comment)

http://orange-development.readthedocs.io/widget.html#input-output-signal-definitions

First, thank you for working on the Orange add-on. It's greatly appreciated!

However, this add-on is already registered with Orange, but it looks like it is still in development phase. Would you mind adding a description on what this add-on does in about.md file? Also perhaps indicate it is still in development mode.

Thank you!