Feature request: Callback for opening a project

[naddeoa]

Firstly, thanks a ton for the plugin; it is part of my core vim workflow!

Could you tell me a little bit about what would have to change to enable a callback for opening a project from the welcome screen? I'm using your project in combination with the vim session plugin and I would love to have my vim session automatically restore when I pick the project. Right now I just execute :OpenSession, and that works, but it could be better.