Merge pull request #104 from php-http/dev-sf31

Test for Symfony3.1

Author: dbu

.travis.yml

@@ -16,6 +16,7 @@ env:
     global:
         - TEST_COMMAND="composer test"
     matrix:
+        - SYMFONY_VERSION=3.1.*
         - SYMFONY_VERSION=3.0.*
         - SYMFONY_VERSION=2.8.*
         - SYMFONY_VERSION=2.7.*