Implement import costume button
Rename ScriptEditor, CostumeEditor, and SoundEditor
Rename CSS classes for ScriptsPanel, CostumesPanel, and SoundsPanel
Add ImageEditor
Add settings pane to image editor
Install image editor in app
Add color picker swatch button
Add color picker wheel button
Add foreground/background colors to paint editor
Add eyedropper button to color picker
Add hover style to eyedropper button
Add Chrome app manifest and background page
Change bounds => innerBounds
Select newly created costumes