PhpDumper heritable

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

The PhpDumper is a really useful component, because is the responsible of write the project container cache, the people should be able to customize his framework.
For example in our personal case, we want to write the behavior of the getDefaultParameters() in the project container cache. (We need don't compile the parameters, and we want to rewrite this for:

     /**
      * @param $parameters
      * @return string
      */
     protected function getCodeForGetDefaultParameters($parameters)
     {
         return <<<EOF
  
      /**
       * Gets the default parameters.
       *
       * @return array An array of the default parameters
       */
      protected function getDefaultParameters()
      {
          return include("foo/our_custom_and_not_cachable_parameters.php");
      }
 
     EOF;
 
         return $code;
      }

**Developers should be able to rewrite any behavior of this very important component of symfony.
Symfony should be a flexible framework.**