Fixed I18n handlebars helpers to update when locale changes

Via the console, you can Travis.set('locale', 'ja') and all the labels
will properly update. This should work on User#updateLocale as well but
I am having a devil of a time testing it locally as I cannot sign in.

assets/scripts/app/helpers.coffee

@@ -1,3 +1,4 @@
 require 'helpers/handlebars'
 require 'helpers/helpers'
 require 'helpers/urls'
+require 'helpers/i18n_handlebars'

assets/scripts/app/helpers/handlebars.coffee

@@ -6,9 +6,6 @@ safe = (string) ->
 Handlebars.registerHelper 'tipsy', (text, tip) ->
   safe '<span class="tool-tip" original-title="' + tip + '">' + text + '</span>'
 
-Handlebars.registerHelper 't', (key) ->
-  safe I18n.t(key)
-
 Ember.registerBoundHelper 'capitalize', (value, options) ->
   if value?
     safe $.capitalize(value)

assets/scripts/app/helpers/i18n_handlebars.coffee

@@ -0,0 +1,34 @@
+I18nBoundView = Ember.View.extend Ember._Metamorph, {
+
+  key: null,
+
+  valueDidChange: ->
+    return if this.morph.isRemoved()
+    this.morph.html(this.valueForRender())
+
+  valueForRender: ->
+    new Handlebars.SafeString I18n.t(this.key)
+
+  init: ->
+    this._super()
+    Travis.addObserver('locale', this, 'valueDidChange')
+
+  didInsertElement: ->
+    this.valueDidChange()
+
+  destroy: ->
+    Travis.removeObserver('locale', this, 'valueDidChange')
+    this._super()
+
+  render: (buffer) ->
+    buffer.push(this.valueForRender())
+}
+
+Ember.Handlebars.registerHelper 't', (key, options) ->
+  view = options.data.view
+  bindView = view.createChildView(I18nBoundView, { key: key })
+  view.appendChild(bindView)
+  # dont write any content from this helper, let the child view
+  # take care of itself.
+  false
+

assets/scripts/app/models/user.coffee

@@ -32,6 +32,7 @@ require 'travis/model'
   ).property()
 
   updateLocale: (locale) ->
+    Travis.set 'locale', locale
     @setWithSession('locale', locale)
 
     transaction = @get('transaction')

assets/scripts/travis.coffee

@@ -64,10 +64,7 @@ Storage = Em.Object.extend
   setLocale: (locale) ->
     return unless locale
     I18n.locale = locale
-    @storage.setItem('travis.locale', locale)
-
-  needsLocaleChange: (locale) ->
-    I18n.locale != locale
+    Travis.set('locale', locale)
 
   storage: (->
     storage = null
@@ -96,7 +93,7 @@ Storage = Em.Object.extend
     location.href = location.href.replace('#!/', '') if location.hash.slice(0, 2) == '#!'
 
     I18n.fallbacks = true
-    @setLocale @storage.getItem('travis.locale') || 'en'
+    Travis.set 'locale', 'en'
 
     Ember.run.next this, ->
       app = Travis.App.create(attrs || {})