Update titles after adding/removing tabs

The duplicate title detection requires the tab be on the DOM
so update the title after it is inserted and also update titles
of remaining tabs after one is removed so long titles being used
can go back to short titles if no other tab title duplicates exist.

Closes #446

src/packages/tabs/lib/tab-bar-view.coffee

@@ -47,9 +47,11 @@ class TabBarView extends SortableList
       tab.insertBefore(followingTab)
     else
       @append(tab)
+    tab.updateTitle()
 
   removeTabForItem: (item) ->
     @tabForItem(item).remove()
+    tab.updateTitle() for tab in @getTabs()
 
   getTabs: ->
     @children('.tab').toArray().map (elt) -> $(elt).view()

src/packages/tabs/spec/tabs-spec.coffee

@@ -88,6 +88,17 @@ describe "TabBarView", ->
       expect(tabBar.getTabs().length).toBe 2
       expect(tabBar.find('.tab:contains(Item 2)')).not.toExist()
 
+    it "updates the titles of the remaining tabs", ->
+      expect(tabBar.tabForItem(item2)).toHaveText 'Item 2'
+      item2.longTitle = '2'
+      item2a = new TestView('Item 2')
+      item2a.longTitle = '2a'
+      pane.showItem(item2a)
+      expect(tabBar.tabForItem(item2)).toHaveText '2'
+      expect(tabBar.tabForItem(item2a)).toHaveText '2a'
+      pane.removeItem(item2a)
+      expect(tabBar.tabForItem(item2)).toHaveText 'Item 2'
+
   describe "when a tab is clicked", ->
     it "shows the associated item on the pane and focuses the pane", ->
       spyOn(pane, 'focus')