PHP Updates

This pull adds php 5.6.0, and also updates php 5.3.3 and 5.5.9's xdebug to 2.2.5.

**Before this pull:**

| PHP Version | Additional Alias | Xdebug Version |
| --- | --- | --- |
| 5.3.3 | - | **2.2.0** |
| 5.3.29 | 5.3 | 2.2.5 |
| 5.4.32 | 5.4 | 2.2.5 |
| 5.5.9 | - | **2.2.3** |
| 5.5.16 | 5.5 | 2.2.5 |
| **5.6.0RC4** | 5.6 | 2.2.5 |

**After this pull:**

| PHP Version | Additional Alias | Xdebug Version |
| --- | --- | --- |
| 5.3.3 | - | **2.2.5** |
| 5.3.29 | 5.3 | 2.2.5 |
| 5.4.32 | 5.4 | 2.2.5 |
| 5.5.9 | - | **2.2.5** |
| 5.5.16 | 5.5 | 2.2.5 |
| **5.6.0** | 5.6 | 2.2.5 |

---

Additional things to note:
* The xdebug updates fix [some issues](http://xdebug.org/updates.php), and in particular, phpunit requires at least 2.2.3 to run it's code coverage stuff properly. See http://phpunit.de/manual/4.2/en/installation.html#installation.requirements.
* The php 5.6.0 update was sent to [php-build](https://github.com/CHH/php-build) as https://github.com/CHH/php-build/commit/8b4aee7243a18d7ab48637fe01e11b1996777bd2.
* The xdebug 2.2.5 updates were sent to [php-build](https://github.com/CHH/php-build) as https://github.com/CHH/php-build/commit/e8bed9a42de85d51bd547bbd8e89baa1d45e1a72.