Fix scrolling of Launcxher FirstRun

Johnathan R pointed out that for wider windows, the button was
invisible, fix this will a scrollbar.

src/GUI/qml/FirstRun.qml

@@ -3,10 +3,25 @@ import FlightGear 1.0
 import FlightGear.Launcher 1.0
 import "."
 
-Rectangle {
-    color: Style.themeColor
+Item {
     id: root
 
+    Rectangle {
+        id: content
+        color: Style.themeColor
+        anchors.fill: parent
+
+    }
+
+    Flickable {
+        id: flick
+
+        contentHeight: textColumn.childrenRect.height + imageClipFrame.height + (Style.strutSize * 2)
+        flickableDirection: Flickable.VerticalFlick
+
+        anchors.fill: parent
+
+
         Item  {
             id: imageClipFrame
             clip: true
@@ -59,6 +74,7 @@ Rectangle {
 
 
         Column {
+            id: textColumn
             anchors {
                 left: parent.left
                 right: parent.right
@@ -134,7 +150,15 @@ Rectangle {
             }
         } // of column
 
+    } // of Flickable
 
 
+    Scrollbar {
+        id: scrollbar
+        anchors.right: parent.right
+        height: flick.height
+        flickable: flick
+        visible: flick.contentHeight > flick.height
+    }
 
-}
+} // of Item