Merge pull request #23 from ddeboer/stable-http-message

Depend on stable psr/http-message

Author: sagikazarmark

composer.json

@@ -12,7 +12,7 @@
     ],
     "require": {
         "php": ">=5.4",
-        "psr/http-message": "^0.11"
+        "psr/http-message": "~1.0"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.4"