Narrow windows left after restart

[slavaGanzin]

Hello.

Not closed narrow panes will reappear after restart or project load, and they are non operating: you can't use them as regular.

So I add this to my init file:

atom.packages.onDidActivatePackage (pack) ->
  Array.from(atom.textEditors.editors)
    .filter (e) -> e.getGrammar().name == 'Narrow'
    .map (x) -> x.destroy()

But I think narrow should close his panes on init. So I can make PR if you would merge.

Thanks