Add sudo:false to travis so that containers are used.

http://docs.travis-ci.com/user/migrating-from-legacy/?utm_source=legacy-notice&utm_medium=banner&utm_campaign=legacy-upgrade

.travis.yml

@@ -3,3 +3,4 @@ node_js:
  - "0.10"
 before_script: make dev
 script: make check
+sudo: false