PHP Warning fix + extraParameters from config

1. Fixed PHP Warning: If we're using Resque - we are almost guaranteed to load it ourselves in order to configure it. Since `class_exists()` tries to autoload by default, this raises a PHP Warning every time an exception is handled. Setting `$autoload=false` on the parameter list makes sure it only tests for already existing Resque, not attempt to include it as well.
2. You can now include 'extraParameters' in your configuration as well and it will be sent to Airbrake's "parameters" field (used to have to be hard coded?)
Wouldn't you load it in some way before, though? You'd have to configure it, right? What happens now is that I don't use Resque at all, so every time I have an exception that needs to be handled by Airbrake, I get the following warning as well:

    PHP Warning:  include(Resque.php): failed to open stream: No such file or directory in /var/www/WisePricer/wisepricer/yii/framework/YiiBase.php on line 418
    PHP Stack trace:
    PHP   1. CApplication->handleException() /var/www/WisePricer/wisepricer/yii/framework/base/CApplication.php:0
    PHP   2. CErrorHandler->handle() /var/www/WisePricer/wisepricer/yii/framework/base/CApplication.php:714
    PHP   3. MErrorHandler->handleException() /var/www/WisePricer/wisepricer/yii/framework/base/CErrorHandler.php:108
    PHP   4. Airbrake\Client->notifyOnException() /var/www/WisePricer/wisepricer/wpyii/protected/extensions/yii-airbrake/MErrorHandler.php:33
    PHP   5. Airbrake\Client->notify() /var/www/WisePricer/wisepricer/wpyii/protected/modules/Airbrake/Client.php:95
    PHP   6. class_exists() /var/www/WisePricer/wisepricer/wpyii/protected/modules/Airbrake/Client.php:108
    PHP   7. spl_autoload_call() /var/www/WisePricer/wisepricer/wpyii/protected/modules/Airbrake/Client.php:108
    PHP   8. YiiBase::autoload() /var/www/WisePricer/wisepricer/wpyii/protected/modules/Airbrake/Client.php:0

Another solution I can think of, is make it configurable via the Configure class (and make the default true, as it was before)