I think Travis now disallows sudo.

In the new container-based builds.

.travis.yml

@@ -4,16 +4,16 @@ python:
 install: 
   # Supposed to help get PIL to install on PyPi
   # https://github.com/python-imaging/Pillow/issues/570
-  - sudo apt-get install python-tk
+  - apt-get install python-tk
 
   # To install external filter binaries, we first need to install
   # RubyGems and Node/NPM. I'm not sure why, since it seems clear
   # that NVM and RVM are pre-installed (see below).
-  - sudo apt-get install python-software-properties
-  - sudo apt-add-repository -y ppa:chris-lea/node.js
-  - sudo apt-get update
-  - sudo apt-get install nodejs rubygems
-  - sudo apt-get install npm
+  - apt-get install python-software-properties
+  - apt-add-repository -y ppa:chris-lea/node.js
+  - apt-get update
+  - apt-get install nodejs rubygems
+  - apt-get install npm
   - npm install -g postcss autoprefixer
 
   # These are useful for debugging this mess.
@@ -23,7 +23,7 @@ install:
 
   # Use non-http registry? https://github.com/n1k0/casperjs/issues/876
   # Without this, installing doesn't work.  
-  - sudo npm config set registry http://registry.npmjs.org/
+  - npm config set registry http://registry.npmjs.org/
 
   # Now install the external filter binaries, finally. 
   # If we use sudo for this, ruby gems will not work: it seems they are