PSR-2 and some other style changes

Code sniffer running wild again … :running:

Also changed in Async.php
```php
public function addstack($filename = "", Silex\Application $app)
```
to
```php
public function addstack($filename, Silex\Application $app)
```
and
```php
public function filebrowser($contenttype = 'pages', Silex\Application $app, Request $request)
```
to
```php
public function filebrowser($contenttype, Silex\Application $app, Request $request)
```
I think that should make no problem?!