Fixes #819 Privacy violation and other issues with - Drafts

Fixes #819 Privacy violation and other issues with - Drafts
Same file:
```PHP
$where_sql .= " AND w.uid='{$search['uid']}'";
```

`showthread.php`:
```PHP
$visibleonly2 = "AND (p.visible='1' OR p.visible='0') AND (t.visible='1' OR t.visible='0')";
```

@Destroy666x for 1.8 maybe.