Workaround patch for no_tag filtering

[vit1-irk]

Hi! Several people reported issues with annoying scrolling when trying to tag a lot of untagged bookmarks.
#41 #12

I've done a quick patch for no_tag filter to make bookmarks app a little more usable. (apply to current master)
Usage: write "_notag" in the tags filter search bar.

diff --git a/controller/lib/bookmarks.php b/controller/lib/bookmarks.php
index e0fe466..8baf6c4 100644
--- a/controller/lib/bookmarks.php
+++ b/controller/lib/bookmarks.php
@@ -187,6 +187,20 @@ class Bookmarks {
        return $bookmarks;
    }

+   public static function findUntaggedBookmarks($userId, IDb $db, $offset, $limit = 10) {
+       $sql = "SELECT * FROM `*PREFIX*bookmarks` where `id` not in (select `bookmark_id` from `*PREFIX*bookmarks_tags`) AND `user_id` = ?";
+
+       if ($limit == -1 || $limit === false) {
+           $limit = null;
+           $offset = null;
+       }
+
+       $query = $db->prepareQuery($sql, $limit, $offset);
+       $results = $query->execute(array($userId))->fetchAll();
+
+       return $results;
+   }
+
    private static function findBookmarksBuildFilter(&$sql, &$params, $filters, $filterTagOnly, $tagFilterConjunction, $CONFIG_DBTYPE) {
        $tagOrSearch = false;
        $connectWord = 'AND';
diff --git a/controller/rest/bookmarkcontroller.php b/controller/rest/bookmarkcontroller.php
index cd6597b..a9d53a5 100644
--- a/controller/rest/bookmarkcontroller.php
+++ b/controller/rest/bookmarkcontroller.php
@@ -66,16 +66,21 @@ class BookmarkController extends ApiController {
            $qtags = Bookmarks::findTags($this->userId, $this->db, $tags);
            return new JSONResponse(array('data' => $qtags, 'status' => 'success'));
        } else { // type == bookmark
-           $filterTag = Bookmarks::analyzeTagRequest($tag);
-
            $offset = $page * 10;

-           if ($sort == 'bookmarks_sorting_clicks') {
-               $sqlSortColumn = 'clickcount';
-           } else {
-               $sqlSortColumn = 'lastmodified';
+           if ($tag == "_notag") {
+               $bookmarks = Bookmarks::findUntaggedBookmarks($this->userId, $this->db, $offset);
+           }
+           else {
+               $filterTag = Bookmarks::analyzeTagRequest($tag);
+
+               if ($sort == 'bookmarks_sorting_clicks') {
+                   $sqlSortColumn = 'clickcount';
+               } else {
+                   $sqlSortColumn = 'lastmodified';
+               }
+               $bookmarks = Bookmarks::findBookmarks($this->userId, $this->db, $offset, $sqlSortColumn, $filterTag, true);
            }
-           $bookmarks = Bookmarks::findBookmarks($this->userId, $this->db, $offset, $sqlSortColumn, $filterTag, true);
            return new JSONResponse(array('data' => $bookmarks, 'status' => 'success'));
        }
    }

Hope somebody found this patch useful.