Add some widget layout and ability event handling.

src/ui_elements/widgets/Widget.cpp

@@ -7,6 +7,7 @@ Widget::Widget()
     : mLocation(DiscretePoint(0, 0)),
       mWidth(100),
       mHeight(100),
+      mMaxHeight(0),
       mMyLayers(),
       mLayers(),
       mChildren(),
@@ -50,6 +51,16 @@ std::vector<VisualLayer*> Widget::GetLayers() const
     return mLayers;
 }
 
+unsigned Widget::GetMaxHeight() const
+{
+    return mMaxHeight;
+}
+
+void Widget::SetMaxHeight(unsigned maxHeight)
+{
+    mMaxHeight = maxHeight;
+}
+
 void Widget::CopyMyLayers()
 {
     mLayers.clear();