use a list for tabs

src/packages/tabs/src/tab.coffee

@@ -4,7 +4,7 @@ fs = require 'fs'
 module.exports =
 class Tab extends View
   @content: (editSession) ->
-    @div class: 'tab', =>
+    @li class: 'tab', =>
       @span class: 'file-name', outlet: 'fileName'
       @span class: 'close-icon'
 

src/packages/tabs/src/tabs-view.coffee

@@ -13,7 +13,7 @@ class Tabs extends View
       pane.prepend(new Tabs(editor))
 
   @content: ->
-    @div class: 'tabs'
+    @ul class: 'tabs'
 
   initialize: (@editor) ->
     for editSession, index in @editor.editSessions