implemented base UI keyframe functionality

This commit implements much of the base functionality for creating and
destroying keyframes in the UI. Not complete yet, but getting there.

app/widget/keyframeview/keyframeview.cpp

@@ -10,6 +10,23 @@ KeyframeView::KeyframeView(QWidget *parent) :
   setDragMode(QGraphicsView::RubberBandDrag);
 }
 
+void KeyframeView::AddKeyframe(NodeKeyframePtr key, int y)
+{
+  QPoint global_pt(0, y);
+  QPoint local_pt = mapFromGlobal(global_pt);
+  QPointF scene_pt = mapToScene(local_pt);
+
+  KeyframeViewItem* item = new KeyframeViewItem(key, scene_pt.y());
+  item->SetScale(scale_);
+  item_map_.insert(key.get(), item);
+  scene()->addItem(item);
+}
+
+void KeyframeView::RemoveKeyframe(NodeKeyframePtr key)
+{
+  delete item_map_.value(key.get());
+}
+
 void KeyframeView::mousePressEvent(QMouseEvent *event)
 {
   if (PlayheadPress(event)) {
@@ -36,3 +53,12 @@ void KeyframeView::mouseReleaseEvent(QMouseEvent *event)
 
   QGraphicsView::mouseReleaseEvent(event);
 }
+
+void KeyframeView::ScaleChangedEvent(double scale)
+{
+  QMap<NodeKeyframe*, KeyframeViewItem*>::const_iterator iterator;
+
+  for (iterator=item_map_.begin();iterator!=item_map_.end();iterator++) {
+    iterator.value()->SetScale(scale);
+  }
+}