Backport some changes from PHP HTTP

Author: sagikazarmark

.travis.yml

@@ -28,7 +28,7 @@ matrix:
           env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest" COVERAGE=true TEST_COMMAND="composer test-ci"
 
 before_install:
-    - if [[ $COVERAGE != true && $TRAVIS_PHP_VERSION != hhvm ]]; then phpenv config-rm xdebug.ini; fi
+    - if [[ $COVERAGE != true ]]; then phpenv config-rm xdebug.ini || true; fi
 
 install:
     # To be removed when this issue will be resolved: https://github.com/composer/composer/issues/5355

composer.json

@@ -11,7 +11,7 @@
         }
     ],
     "require": {
-        "php": ">=5.5"
+        "php": "^5.5 || ^7.0"
     },
     "autoload": {
         "psr-4": {