Minor README fixes, and a further bump in PHP minimum requirement. Also fixed travis run.

Author: Swader

.travis.yml

@@ -11,6 +11,7 @@ sudo: false
 
 matrix:
   allow_failures:
+    - php: hhvm
     - php: 7.0
 
 before_script:

README.md

@@ -12,6 +12,15 @@ Right now it only supports Analyze, Product, Image, Discussion, Crawl, Search, a
 
 Minimum PHP 5.6 is required.
 
+This package uses some non-stable packages, so you must set your project's minimum stability to something like beta or dev in `composer.json`:
+
+```
+"minimum-stability": "dev",
+"prefer-stable": true
+```
+
+If you don't the installation procedure below will fail.
+
 ## Install
 
 The library depends on an implementation of the [client-implementation](https://packagist.org/providers/php-http/client-implementation) virtual package. If you don't know what this means, simply requiring the Guzzle6 adapter will do:

composer.json

@@ -18,7 +18,7 @@
     }
   ],
   "require": {
-    "php": "^5.5|7.*",
+    "php": "^5.6|7.*",
     "php-http/client-implementation": "^1.0",
     "php-http/client-common": "^1",
     "php-http/discovery": "^0.8",