update to node 0.10

.travis.yml

 language: node_js
 node_js:
-  - 0.8
+  - 0.10
 before_script:
-  - npm update -g npm
\ No newline at end of file
+  - npm install -g grunt-cli
\ No newline at end of file

package.json

@@ -18,7 +18,7 @@
     "url": "git://github.com/hakimel/reveal.js.git"
   },
   "engines": {
-    "node": "~0.8.0"
+    "node": "~0.10.0"
   },
   "dependencies": {
     "underscore": "~1.5.1",