Added action for togling fullscreen

Contributes to CURA-52

resources/qml/Actions.qml

@@ -40,6 +40,14 @@ Item {
     property alias reportBug: reportBugAction;
     property alias about: aboutAction;
 
+    property alias toggleFullScreen: toggleFullScreenAction;
+
+    Action
+    {
+        id:toggleFullScreenAction
+        shortcut: StandardKey.FullScreen;
+    }
+
     Action {
         id: undoAction;
         //: Undo action

resources/qml/Cura.qml

@@ -12,7 +12,6 @@ import UM 1.1 as UM
 UM.MainWindow {
     id: base
     visible: true
-
     //: Cura application window title
     title: qsTr("Cura");
 
@@ -425,6 +424,8 @@ UM.MainWindow {
         reportBug.onTriggered: CuraActions.openBugReportPage();
         showEngineLog.onTriggered: engineLog.visible = true;
         about.onTriggered: aboutDialog.visible = true;
+        toggleFullScreen.onTriggered: base.toggleFullscreen()
+
     }
 
     Menu {