Full support for other units, add configuration option for default unit (used when displaying amounts)

src/qt/qvaluecombobox.h

@@ -0,0 +1,33 @@
+#ifndef QVALUECOMBOBOX_H
+#define QVALUECOMBOBOX_H
+
+#include <QComboBox>
+
+// QComboBox that can be used with QDataWidgetMapper to select
+// ordinal values from a model.
+class QValueComboBox : public QComboBox
+{
+    Q_OBJECT
+    Q_PROPERTY(int value READ value WRITE setValue NOTIFY valueChanged USER true);
+public:
+    explicit QValueComboBox(QWidget *parent = 0);
+
+    int value() const;
+    void setValue(int value);
+
+    // Model role to use as value
+    void setRole(int role);
+
+signals:
+    void valueChanged();
+
+public slots:
+
+private:
+    int role;
+
+private slots:
+    void handleSelectionChanged(int idx);
+};
+
+#endif // QVALUECOMBOBOX_H