Travis: Update NPM to support new dependency glob

"^" dependency versions break in the version of NPM that ships with 0.8
Using https://www.npmjs.org/doc/misc/npm-faq.html#How-do-I-update-npm to ensure the CI build keeps testing for now

Author: nschonni

.travis.yml

@@ -4,4 +4,5 @@ node_js:
   - "0.10"
   - "0.11"
 before_install:
+  - npm update npm -g # For "^" dependency compatiblibty in NodeJS 0.8
   - npm install -g grunt-cli