Prompt user to title notebook

[doolittle]

When a user pushes "save" on a notebook for the first time and has not changed the title from "New Notebook," let's show a modal asking the user to title the notebook.

The modal would be very simple--a title (i.e. "Name your notebook"), instructions, an input field, and a save button. The default title would be "New Notebook" and the user could just push save without changing the title.