Import View superclasses from atom-space-pen-views library
Call addOpener instead of registerOpener
:arrow_up: atom-space-pen-views
Use File::onDidDelete to subscribe to deletion event
:arrow_up: pathwatcher for deprecation warning fix
Use File::onDidChange to watch for contents changing
Remove atom.workspaceView
:arrow_up: atom-space-pen-views for newest space-pen dependency
Merge pull request #14 from atom/ns-modernize

Remove usage of deprecated APIs