qml: Add flip-vertical icon

The flip-veritcal icon is primarily used when flipping the units
displayed when clicked

Author: johnny9

src/Makefile.qt.include

@@ -341,6 +341,7 @@ QML_RES_ICONS = \
   qml/res/icons/cross.png \
   qml/res/icons/error.png \
   qml/res/icons/export.png \
+  qml/res/icons/flip-vertical.png \
   qml/res/icons/gear.png \
   qml/res/icons/gear-outline.png \
   qml/res/icons/hidden.png \

src/qml/bitcoin_qml.qrc

@@ -98,6 +98,7 @@
         <file alias="cross">res/icons/cross.png</file>
         <file alias="error">res/icons/error.png</file>
         <file alias="export">res/icons/export.png</file>
+        <file alias="flip-vertical">res/icons/flip-vertical.png</file>
         <file alias="gear">res/icons/gear.png</file>
         <file alias="gear-outline">res/icons/gear-outline.png</file>
         <file alias="hidden">res/icons/hidden.png</file>

src/qml/imageprovider.cpp

@@ -97,6 +97,11 @@ QPixmap ImageProvider::requestPixmap(const QString& id, QSize* size, const QSize
         return QIcon(":/icons/export").pixmap(requested_size);
     }
 
+    if (id == "flip-vertical") {
+        *size = requested_size;
+        return QIcon(":/icons/flip-vertical").pixmap(requested_size);
+    }
+
     if (id == "gear") {
         *size = requested_size;
         return QIcon(":/icons/gear").pixmap(requested_size);