Add SharingMiddleware for permission checks and small fixes

lib/Service/BoardService.php

@@ -66,13 +66,7 @@ class BoardService {
 
     public function find($userId, $boardId) {
         $board = $this->boardMapper->find($boardId);
-        if ($board->getOwner() === $userId)
-            return $board;
-        else
-            return null;
-
-        // FIXME: [share] Check for user permissions
-
+        return $board;
     }
 
     public function create($title, $userId, $color) {

lib/Service/LabelService.php

@@ -51,7 +51,6 @@ class LabelService  {
 
     public function find($userId, $labelId) {
         $label = $this->labelMapper->find($labelId);
-        // FIXME: [share] Check for user permissions
         return $label;
     }