Fixed crash on add item via favorite button after application start.

Favorite buttons has short name labels.
closes #296
refs #293

shop/data/favorititem.cpp

@@ -28,6 +28,16 @@ void FavoritItem::setName(const QString &name)
     m_name = name;
 }
 
+QString FavoritItem::shortName()
+{
+    return m_shortName;
+}
+
+void FavoritItem::setShortName(const QString &shortName)
+{
+    m_shortName = shortName;
+}
+
 QDecDouble FavoritItem::unitPrice()
 {
     return TO_DEC(m_unitPrice);