Show monitor guides on effects scenes.

Fixes #141

src/monitor/view/EffectToolBar.qml

@@ -47,6 +47,19 @@ Rectangle {
             tooltip: i18n("Switch Full Screen")
             onClicked: controller.triggerAction('monitor_fullscreen')
         }
+        ToolButton {
+            objectName: "switchOverlay"
+            iconName: "view-grid"
+            tooltip: i18n("Change Overlay")
+            onClicked: {
+                if (controller.overlayType >= 5) {
+                    controller.overlayType = 0
+                } else {
+                    controller.overlayType = controller.overlayType + 1;
+                }
+                root.overlayType = controller.overlayType
+            }
+        }
         ToolButton {
             objectName: "nextKeyframe"
             iconName: "go-next"

src/monitor/view/SceneToolBar.qml

@@ -55,7 +55,12 @@ Rectangle {
             iconName: "view-grid"
             tooltip: i18n("Change Overlay")
             onClicked: {
-                root.switchOverlay()
+                if (controller.overlayType >= 5) {
+                    controller.overlayType = 0
+                } else {
+                    controller.overlayType = controller.overlayType + 1;
+                }
+                root.overlayType = controller.overlayType
             }
         }
         ToolButton {

src/monitor/view/kdenlivemonitorcornerscene.qml

@@ -11,6 +11,8 @@ Item {
     property string framenum
     property rect framesize
     property point profile: controller.profile
+    property int overlayType: controller.overlayType
+    property color overlayColor: 'cyan'
     property point center
     property double scalex
     property double scaley
@@ -151,6 +153,26 @@ Item {
         y: root.center.y - height / 2 - root.offsety
         color: "transparent"
         border.color: "#ffffff00"
+        Loader {
+            anchors.fill: parent
+            source: {
+                switch(root.overlayType)
+                {
+                    case 0:
+                        return '';
+                    case 1:
+                        return "OverlayStandard.qml";
+                    case 2:
+                        return "OverlayMinimal.qml";
+                    case 3:
+                        return "OverlayCenter.qml";
+                    case 4:
+                        return "OverlayCenterDiagonal.qml";
+                    case 5:
+                        return "OverlayThirds.qml";
+                }
+            }
+        }
     }
     MouseArea {
         id: global

src/monitor/view/kdenlivemonitoreffectscene.qml

@@ -12,6 +12,8 @@ Item {
     property rect framesize
     property rect adjustedFrame
     property point profile: controller.profile
+    property int overlayType: controller.overlayType
+    property color overlayColor: 'cyan'
     property point center
     property double scalex
     property double scaley
@@ -152,6 +154,26 @@ Item {
         y: root.center.y - height / 2 - root.offsety;
         color: "transparent"
         border.color: "#ffffff00"
+        Loader {
+            anchors.fill: parent
+            source: {
+                switch(root.overlayType)
+                {
+                    case 0:
+                        return '';
+                    case 1:
+                        return "OverlayStandard.qml";
+                    case 2:
+                        return "OverlayMinimal.qml";
+                    case 3:
+                        return "OverlayCenter.qml";
+                    case 4:
+                        return "OverlayCenterDiagonal.qml";
+                    case 5:
+                        return "OverlayThirds.qml";
+                }
+            }
+        }
     }
     MouseArea {
         id: global

src/monitor/view/kdenlivemonitorrotoscene.qml

@@ -13,6 +13,8 @@ Item {
     property point profile: controller.profile
     property point center
     property real baseUnit: fontMetrics.font.pixelSize * 0.8
+    property int overlayType: controller.overlayType
+    property color overlayColor: 'cyan'
     property double scalex : 1
     property double scaley : 1
     property double stretch : 1
@@ -302,6 +304,26 @@ Item {
         y: root.center.y - height / 2 - root.offsety;
         color: "transparent"
         border.color: "#ffffff00"
+        Loader {
+            anchors.fill: parent
+            source: {
+                switch(root.overlayType)
+                {
+                    case 0:
+                        return '';
+                    case 1:
+                        return "OverlayStandard.qml";
+                    case 2:
+                        return "OverlayMinimal.qml";
+                    case 3:
+                        return "OverlayCenter.qml";
+                    case 4:
+                        return "OverlayCenterDiagonal.qml";
+                    case 5:
+                        return "OverlayThirds.qml";
+                }
+            }
+        }
     }
 
     Rectangle {