Adjust .travis.yml to run more versions of PHP as well as HHVM

Author: stloyd

.travis.yml

@@ -1,14 +1,43 @@
 language: php
 
 php:
-    - 5.3
-    - 5.4
-    - 5.5
-    - 5.6
-    - hhvm
+  - 7.0
+  - 5.6
+  - 5.3
+  - hhvm
 
-install:
-    - composer install
+sudo: false
 
-script:
-    - vendor/bin/phpunit
+cache:
+  directories:
+    - ~/.composer/cache/files
+
+matrix:
+  fast_finish: true
+  include:
+    - php: 5.3
+      env: COMPOSER_FLAGS="--prefer-lowest"
+    - php: 5.6
+      env: SYMFONY_VERSION=2.3.*
+    - php: 5.6
+      env: SYMFONY_VERSION=2.7.*
+    - php: 5.6
+      env: SYMFONY_VERSION=2.8.*
+    - php: 7.0
+      env: SYMFONY_VERSION=3.0.*
+    - php: 7.0
+      env: SYMFONY_VERSION=3.1.*
+  allow_failures:
+    - php: hhvm
+
+before_install:
+  - if [[ "$TRAVIS_PHP_VERSION" != "hhvm" ]]; then phpenv config-rm xdebug.ini; fi;
+  - if [[ "$TRAVIS_PHP_VERSION" != "hhvm" ]]; then echo "memory_limit=2G" >> ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini; fi;
+
+before_script:
+  - composer self-update
+  - if [ "$SYMFONY_VERSION" != "" ]; then composer require "symfony/symfony:${SYMFONY_VERSION}" --dev --no-update; fi;
+  - if [ "$COMPOSER_FLAGS" != "" ]; then composer update --prefer-dist --no-interaction --no-scripts $COMPOSER_FLAGS; fi;
+  - composer install --prefer-dist --no-interaction --no-scripts
+
+script: vendor/bin/phpunit