Stabilized the API

Author: f3ath

README.md

@@ -1,6 +1,7 @@
 # Implementation of [JSON API](http://jsonapi.org) in PHP
 This library is an attempt to express business rules of JSON API specification in a set of PHP 7 classes.
-While it is still in `0.*` versions, there are no major changes expected in the internal API.
+
+*While it is still in `0.*` versions, there are no major changes expected in the internal API.*
 
 A simple example to illustrate the general idea. This (slightly modified) JSON representation from
 [the documentation](http://jsonapi.org/format/#document-resource-objects)