Revert ae7dce4575.

Now require('package') won't wrong resolve to the package.json, so
reverting previous workaround.

src/app/atom-package.coffee

@@ -1,5 +1,5 @@
 TextMateGrammar = require 'text-mate-grammar'
-Package = require 'base-package'
+Package = require 'package'
 fsUtils = require 'fs-utils'
 _ = require 'underscore'
 $ = require 'jquery'

src/app/atom.coffee

@@ -1,6 +1,6 @@
 fsUtils = require 'fs-utils'
 _ = require 'underscore'
-Package = require 'base-package'
+Package = require 'package'
 Theme = require 'theme'
 ipc = require 'ipc'
 

src/app/text-mate-package.coffee

@@ -1,4 +1,4 @@
-Package = require 'base-package'
+Package = require 'package'
 fsUtils = require 'fs-utils'
 plist = require 'plist'
 _ = require 'underscore'