Tidy up travis.yml - add trusty required

.travis.yml

@@ -1,36 +1,28 @@
 language: php
-
 env:
 - WEB_PORT_80_TCP_ADDR=localhost
-
+sudo: required
+dist: trusty
 php:
     - 5.4
     - 5.5
     - 5.6
     - 7.0
-    #- hhvm
-
-#sudo: false
-
 matrix:
   fast_finish: true
   allow_failures:
     - php: hhvm
-
 cache:
   - apt
-
 addons:
   apt:
     packages:
       - realpath
-
 install:
   - sudo add-apt-repository -y ppa:nginx/stable
   - sudo apt-get update
   - sudo apt-get install -y --force-yes nginx-extras
   - travis/install-nginx.sh
-
 script:
   - sudo nginx -t &> /dev/stdout
   - curl -vsf 'http://localhost:8080/nginx.php' &> /dev/stdout