more natural cmd-w for the tabs pane again

extensions/tabs/tabs-pane.coffee

@@ -50,8 +50,17 @@ class TabsPane extends Pane
     $("#tabs ul li:last").addClass 'active'
 
   closeActiveTab: ->
-    @removeTab $('#tabs ul .active').data 'path'
-    @prevTab()
+    tabsLength = $('#tabs ul li').length
+    activePath = $('#tabs ul .active').data 'path'
+
+    if tabsLength is 1
+      @removeTab activePath
+      $('#main-container').children().css 'display', 'none !important'
+    else if tabsLength > 0
+      @removeTab activePath
+      @prevTab()
+    else
+      window.close()
 
   removeTab: (path) ->
     tab = $("#tabs li[data-path='#{path}']")