Added Code Climate

Code Climate supports PHP

README.md

 * [xHprof](https://github.com/phacility/xhprof) - Another profiling tool for PHP.
 * [PHPCheckstyle](https://github.com/jbrooksuk/phpcheckstyle) - A tool to help adhere to certain coding conventions.
 * [PhpDependencyAnalysis](https://github.com/mamuz/PhpDependencyAnalysis) - A tool to create customisable dependency graphs.
+* [Code Climate](http://codeclimate.com) - An automated code review.
 
 ## Debugging
 *Libraries and tools for debugging code.*