Faster Travis builds

[benbalter]

• Use the container-based infra which usually has a shorter queue
• Cache gems between builds

[parkr]

Looks like timclem.wordpress.com has moved: http://adaptivepatchwork.com/2012/03/01/mind-the-end-of-your-line/

[gjtorikian]

We actually want it to be moved; it's been like that since The Beginning, since the test tests that 301 Redirects are followed.

This looks like another case of the user-agent being flagged:

curl -A 'Typhoeus' -I http://timclem.wordpress.com/2012/03/01/mind-the-end-of-your-line/ 
curl: (52) Empty reply from server

@benbalter If you merge master in here that might solve it.

[benbalter]

Failing test is unrelated (continues to fail on master). I believe it's #200, which wasn't completely fixed by the user agent.