mapwidgetcontextmenu: add a listViewIsVisible integer property

This property would act like a state flag. If -1 (default) no QML State
animation will be pefromed, otherwise the ListView will either fade in
(1), or fade out (0) when the user clicks the context menu button
(Image) or selects an item from the list.

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>

mobile-widgets/qml/MapWidgetContextMenu.qml

@@ -21,6 +21,7 @@ Item {
 			anchors.fill: parent
 			onClicked: {
 				contextMenuImageAnimation.restart()
+				listViewIsVisible = (listViewIsVisible !== 1) ? 1 : 0
 			}
 		}
 	}
@@ -78,4 +79,6 @@ Item {
 			Behavior on color { ColorAnimation { duration: itemAnimationDuration }}
 		}
 	}
+
+	property int listViewIsVisible: -1
 }