Fixes #59, edit text in board view and side pane

* Double-click to start editing
* Press Enter to start editing in board view
* Press Enter to end editing
* Press Esc to cancel editing
* Arrow keys navigate in side pane
* Markup (bold, italic, underline) is properly styled
* Remove some dead code in storyboardstate
* Fix save script bug that causes multiple saves
Cleans up codemirror css
Fixes #88, app crashes on playback

* Fixes playback to not crash in invalid state
* Fixes chunk selector to not be in invalid state
Fixes #105, create player link fails

* Also fixes player to handle new board note format
Resolve merge conflict