Keyboard Shortcut for Save

[jbickelhaupt]

I like the idea of a save feature as you introduced in version 2.12, but it would be nice if you could use command + S (mac) or control + S (pc) to confirm when you want to save an iteration of your project. It would be more efficient than using the mouse to click on the save button, although I think it's good to keep the button as a secondary option.