Add a definition for 5.6.0alpha1.

Fixes #171.
Merge pull request #181 from loicfrering/master

Add a definition for 5.6.0alpha1.
Update README.md
Update README.md
Add core team
Add a definition for 5.6.0alpha2.
Merge pull request #186 from bcremer/add-php-5.6.0alpha2-definition

Add a definition for 5.6.0alpha2.
Added a definition for php 5.6.0alpha3
Bump xdebug to 2.2.4 for php 5.6 alpha 3
Merge pull request #188 from GrahamCampbell/5.6.0alpha3

Added A Definition For PHP 5.6.0 Alpha 3
Updated definitions
Merge pull request #190 from GrahamCampbell/php

5.5.10, 5.5.26, 5.6snapshot