Cleanup serialiser descriptions

README.md

 
 * [Ardent](https://github.com/morrisonlevi/Ardent) - A library of data structures.
 * [PHP Collections](https://github.com/schmittjoh/php-collection) - A simple collections library.
-* [Zend Serializer](https://github.com/zendframework/Component_ZendSerializer) - The library for serialising and de-serialising data (part of Zend Framework 2).
 * [Serializer](https://github.com/schmittjoh/serializer) - A library for serialising and de-serialising data.
+* [Zend Serializer](https://github.com/zendframework/Component_ZendSerializer) - Another library for serialising and de-serialising data (ZF2).
 * [PHP Object Storage](https://github.com/herrera-io/php-object-storage) - A library for object storage.
 * [Fractal](https://github.com/php-loep/fractal) - A library for converting complex data structures to JSON output.
 * [Totem](http://github.com/Wisembly/Totem) - A library to manage and create data changesets.