Add loadThemes() to atom global

src/atom.coffee

@@ -129,6 +129,9 @@ window.atom =
       packages.push(metadata)
     packages
 
+  loadThemes: ->
+    @themes.load()
+
   watchThemes: ->
     @themes.on 'reloaded', =>
       @reloadBaseStylesheets()

src/window.coffee

@@ -45,7 +45,7 @@ window.startEditorWindow = ->
   config.load()
   keymap.loadBundledKeymaps()
   atom.loadBaseStylesheets()
-  atom.themes.load()
+  atom.loadThemes()
   atom.loadPackages()
   deserializeEditorWindow()
   atom.activatePackages()