chore(build): Enable building hyper in docker containers on travis

By stating that hyper does not need sudo to build it can be compiled in
a container:
http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/

.travis.yml

@@ -1,4 +1,5 @@
 language: rust
+sudo: false
 
 script:
     - cargo build