* Extend LiveMarkdown format to support Elixir snippets in Markdown cells
* Highlight Markdown code blocks using Monaco editor API
* Use livebook metadata for forcing markdown as well
* Basic filesystem navigation
* Add file picker modal
* Implement autosave when dirty and show the status
* Add hompage link in the session view
* Improve file picker and use in both places
* Move session list to homepage
* Some refactoring
* Show import messages if any
* Fix and extend tests
* Show a message when there are no sessions running
* Rename import to fork and make that clear in notebook name
* Fix old route
* Show info when no file is connected to the given session
* Show runtime type next to filename
* Show button for joining session when a running path is selected
* Move modal components to SessionLive namespace
* Add FileGuard to lock files used for notebook persistence
* Use radio for specifying persistence type
* Don't lock nil path
* Simplify FileGuard implementation
* Test notebook persistence
* Fix typo
* Further simplify FileGuard
* Improve file listing
* Don't show parent dir when there's a basename being typed
* Add path component tests