Move loadPackages to atom global. Handle '-tmbundle' in regex.

This simplifies the loading of TextMate bundles in the spec and benchmark helpers. Since `loadBundle` was already implemented on `atom`, it made sense to move this logic here. Config is now more focused on its core job of handling configuration, not loading bundles.

benchmark/benchmark-helper.coffee

@@ -11,12 +11,14 @@ TextMateTheme = require 'text-mate-theme'
 require 'window'
 requireStylesheet "jasmine.css"
 
+# Load TextMate bundles, which specs rely on (but not other packages)
+atom.loadPackages(atom.getAvailableTextMateBundles())
+
 beforeEach ->
-  # don't load user configuration
+  # reset config after each benchmark; don't load or save from/to `config.json`
   window.config = new Config()
   spyOn(config, 'load')
   spyOn(config, 'save')
-  config.assignDefaults()
 
 keymap = new Keymap
 keymap.bindDefaultKeys()