* Show all sections and enable cross-section focus navigation
* Move focus to the client
* Add shortcut for evaluating all cells
* Fix and expand tests
* Make section links scroll to the given section
* Set up markdown rendering, update theme.
* Improve focus and handle expanding for markdown cells
* Add keybindings for expanding/navigating cells
* Improve editor autofocus when navigating with shortcuts
* Add tests
* Render markdown on the client
* Don't render cell initial data and make a request instead
* Set up editor and client side delta handling
* Synchronize deltas on the server
* Document the client code, add more tests
* Implement delta on the server, use compact representation when transmitting changes
* Simplify transformation implementation and add documentation
* Add session and data tests
* Add more delta tests
* Clean up evaluator tests wait timeout
