Create new nodes from links when closing a node?

[cjacobwade]

Would be nice to auto create nodes after adding a link to a non-existent node.

[desplesda]

The alternative would be to display some kind of warning that a node is linking to nodes that don't exist.

[com1clyf3]

I'm with @cjacobwade . This feature really enables quick branch design in Twine, and I expected it in Yarn.

[blurymind]

I added this to the electron port today. Will do a merge tonight :)

Here is the pull request
#68