Add a busy indicator which will be overlaid during download

This gives some visual feedback to the post / pool download.

src/qml/danbooruimageview.qml

@@ -29,17 +29,39 @@ import DanbooruClient 1.0
 
 Rectangle {
     id: rootObj
+    objectName: "rootObj"
     width: 500
     height: 500
 
     property bool poolMode: false;
 
+    signal downloadFinished()
+    signal downloadRequested(url url)
+    signal downloadStarted()
+    signal fileInfo(url name, var tags)
+
+
     KRun {
         id: runner
     }
 
-    signal downloadRequested(url url)
-    signal fileInfo(url name, var tags)
+    onDownloadFinished: {
+        runningIndicator.running = false
+    }
+
+    onDownloadStarted: {
+        runningIndicator.running = true
+    }
+
+    BusyIndicator {
+        id: runningIndicator
+        z: 1
+        width: grid.cellWidth / 2
+        height: grid.cellHeight / 2
+        anchors.horizontalCenter: parent.horizontalCenter
+        anchors.verticalCenter: parent.verticalCenter
+        running: false
+    }
 
     Component {
         // This is just for testing
@@ -206,7 +228,8 @@ Rectangle {
             onAtYEndChanged: {
 
                 if (grid.atYEnd && danbooruModel.rowCount() > 0 && !rootObj.poolMode && infiniteScroll) {
-                     danbooruService.nextPostPage();
+                    rootObj.downloadStarted()
+                    danbooruService.nextPostPage();
                 }
             }