Create filters from service manger

Create filters from service manger
```php
    <?php
    // some collection in config file
    'twitter_bootstrap_css' => array(
         'assets' => array(
               '/path/to/bootstrap/file.less'
          ),
         'filters' => array(
               'BootstrapLessCompiler'
         ),
    );
```
Change bootstrap less variables here
```php  
    <?php
    // BootstrapLessCompiler filter factory class
    public function createService(ServiceLocatorInterface $serviceLocator){
            $filter = new LessphpFilter();
            $defaultPresets = $serviceLocator->get('config');
            $defaultPresets = array_merge($defaultPresets['bootstrap_less']['default'], $defaultPresets['bootstrap_less']['application']);
            
            $filter->setPresets($defaultPresets);
            return $filter;
    }
```