Panes destroy their items when they are removed

As a consequence of these changes, editors will no longer need to
listen for destruction of their edit sessions. An editor will
eventually only ever be displaying a single edit session, and the
editor will destroy that edit session when it is removed. Panes
will be responsible for supporting multiple edit sessions, and
they will automatically remove the editor when they have no more
edit session items.

spec/app/pane-spec.coffee

@@ -80,6 +80,10 @@ describe "Pane", ->
         pane.removeItem(editSession1)
         expect(pane.itemViews.find('.editor')).not.toExist()
 
+      it "calls destroy on the model", ->
+        pane.removeItem(editSession2)
+        expect(editSession2.destroyed).toBeTruthy()
+
   describe "pane:show-next-item and pane:show-preview-item", ->
     it "advances forward/backward through the pane's items, looping around at either end", ->
       expect(pane.currentItem).toBe view1
@@ -91,3 +95,9 @@ describe "Pane", ->
       expect(pane.currentItem).toBe editSession2
       pane.trigger 'pane:show-next-item'
       expect(pane.currentItem).toBe view1
+
+  describe ".remove()", ->
+    it "destroys all the pane's items", ->
+      pane.remove()
+      expect(editSession1.destroyed).toBeTruthy()
+      expect(editSession2.destroyed).toBeTruthy()

src/app/editor.coffee

@@ -498,7 +498,7 @@ class Editor extends View
     @editSessions.push(editSession)
     @closedEditSessions = @closedEditSessions.filter ({path})->
       path isnt editSession.getPath()
-    editSession.on 'destroyed', => @editSessionDestroyed(editSession)
+#     editSession.on 'destroyed', => @editSessionDestroyed(editSession)
     @trigger 'editor:edit-session-added', [editSession, index]
     index
 

src/app/pane.coffee

@@ -64,6 +64,7 @@ class Pane extends View
   removeItem: (item) ->
     @showNextItem() if item is @currentItem and @items.length > 1
     _.remove(@items, item)
+    item.destroy?()
     @cleanupItemView(item)
 
   cleanupItemView: (item) ->
@@ -135,6 +136,9 @@ class Pane extends View
       parentAxis.replaceWith(sibling)
     rootView?.adjustPaneDimensions()
 
+  afterRemove: ->
+    item.destroy?() for item in @getItems()
+
   buildPaneAxis: (axis) ->
     switch axis
       when 'row' then new PaneRow