Let me update the repo with something more general than what's there.With Eclipse e4, I could do something like you stated.
I just have simple "Editor" and "View" panes registered as examples, with a feature.You can install the feature in your eclipse environment, then use the editor and view.The editor allows you to double click and edit/run an index.hml file in the workspace, while the view has the index.hml file included in the plugin (runs from views dropdown).Only recently with e4 can you make a little standalone application without all the eclipse rcp (preferences, views, editors, perspectives, etc.)