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

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

commodity/data/commoditydata.cpp

@@ -26,7 +26,7 @@ void CommodityData::setName(const QString &name)
 {
     m_name = name;
 }
-QString CommodityData::shortName() const
+QString CommodityData::shortName()
 {
     return m_shortName;
 }

commodity/data/commoditydata.h

@@ -31,7 +31,7 @@ public:
     QString name() override;
     void setName(const QString &name);
 
-    QString shortName() const;
+    QString shortName() override;
     void setShortName(const QString &shortName);
 
     QString code() const;