Add spec
Don't use WorkspaceView
Use atom-space-pen-views
Use atom.grammars
Suppress deprecation for item implementing ::on
Modernize example markup

* Remove deprecated classes
* Don't use space-pen, except for to demonstrate subclassing SelectListView
Remove unnecessary caching of StyleGuideView class
Remove workspace opener on deactivate
Merge pull request #15 from atom/mb-modernize

Remove use of deprecated APIs