Initial implementation of the embedded notebook. Moves a few deps away from classes to the templates. Zero styles implemented.
Block appending/focusing the next cells when we are in embedded mode.
Implement rough styles.
Add styles for embedded notebook footer. Add icons for play and pop-out. Add tooltips for footer buttons. Add play button to cell controls.
Fix background gradient on embedded footer (oops, background-color doesn't work, but background does).
Make sure button text looks the same as link text.
Add hover state to buttons, lighten background, and shrink font of embedded footer.
Fix loading indicator.
Add header and footer config options.
Add NOTEBOOK_TITLE to readme.
Enforce readonly mode better.