Fix exception module not setting the HTTP response code

- Page->run now returns an updated response for use with Page->exit
- Remove now duplicated header setting in Page->run
- Remove now obsolete (and ineffective) HTTP return code setting from Module\Special\HTTPException->content
- Add HTTP response code and reason setting in BaseModule->run

src/BaseModule.php

@@ -251,6 +251,7 @@ abstract class BaseModule implements ICanHandleRequests
 				throw $e;
 			}
 
+			$this->response->setStatus($e->getCode(), $e->getMessage());
 			$this->response->addContent($httpException->content($e));
 		} finally {
 			$this->profiler->set(microtime(true) - $timestamp, 'content');