Minor changes to Group API to make it more explicit

* Include check for group as recycle bin directly into the Group::isRecycled() function

* Return the original root group from Database::setRootGroup(...) to force memory management transfer

src/core/Entry.cpp

@@ -463,7 +463,7 @@ bool Entry::isRecycled() const
         return false;
     }
 
-    return m_group == db->metadata()->recycleBin() || m_group->isRecycled();
+    return m_group->isRecycled();
 }
 
 bool Entry::isAttributeReference(const QString& key) const