Add clean task

Gruntfile.coffee

@@ -1,3 +1,5 @@
+BUILD_DIR = '/tmp/atom-build'
+
 module.exports = (grunt) ->
   grunt.initConfig
     pkg: grunt.file.readJSON('package.json')
@@ -23,5 +25,16 @@ module.exports = (grunt) ->
   grunt.loadNpmTasks('grunt-coffeelint')
   grunt.loadNpmTasks('grunt-contrib-csslint')
 
+  grunt.registerTask 'clean', 'Delete all build files', ->
+    rm = require('rimraf').sync
+    rm BUILD_DIR
+    rm '/tmp/atom-coffee-cache'
+    rm '/tmp/atom-cached-atom-shells'
+    rm 'node_modules'
+    rm 'atom-shell'
+    rm 'cef'
+    rm 'node'
+    rm 'prebuilt-cef'
+
   grunt.registerTask('lint', ['coffeelint:src', 'coffeelint:test', 'csslint:src'])
   grunt.registerTask('default', 'lint')

package.json

@@ -65,7 +65,8 @@
     "grunt": "~0.4.1",
     "grunt-cli": "~0.1.9",
     "grunt-coffeelint": "0.0.6",
-    "grunt-contrib-csslint": "~0.1.2"
+    "grunt-contrib-csslint": "~0.1.2",
+    "rimraf": "~2.1.4"
   },
   "private": true,
   "scripts": {