Detect Zend OPcache and WinCache as PHP Accelerators

Now opcache, wincache shows "OK" as PHP Accelerators (when present and enabled)
Updated check method, cloning the funcionality used in HttpKernel (ConfigDataCollector.php)
merged branch dangarzon/2.2 (PR #88)

This PR was merged into the 2.2 branch.

Discussion
----------

Detect Zend OPcache and WinCache as PHP Accelerators

Now opcache, wincache shows "OK" as PHP Accelerators (when present and enabled)
Updated check method, cloning the funcionality used in HttpKernel (ConfigDataCollector.php)

This PR replaces #86 (done in branch 2.1), closed because is not maintained anymore.

Commits
-------

6f61889 Detect Zend OPcache and WinCache as PHP Accelerators
Merge branch '2.2'

* 2.2:
  Detect Zend OPcache and WinCache as PHP Accelerators