Added lots to themes and the Theme API.

Themes can now be used to style many common elements, see the “all features” example in bike-extension-kit/api/theme. I think I’m done making big changes to themes. Now’s a good time to explore and report any problems you run into.

• Added Add Link to Row
• Added Pin Row command (⌘Y)
• Added ChoiceBox API (see bike.showChoiceBox())
• Improved sidebar selection logic
• Changed ChoiceBox UI to a standard flat list without preferences
• Changed Show Commands to include more outliner commands
• Changed Sidebar API addAction to addLocation
• Fixed NSOutlineView crash deleting multiple sidebar items
• Fixed Hookmark Mail links (empty queryParameters added ?)
• Fixed autocorrect attribute extraction with substring offsets
• Fixed autocorrect races with rapid keystrokes (I think!)