Add check for parent UI Figure

Previous logic assumed that the parent of the input UI object is the
UI Figure, which is an incorrect assumption. Other containers, like
uipanel, exist and are valid parents for other UI objects but will
cause the object type check to fail.

This type check has been updated to utilize ancestor to obtain the
parent figure window.

See #6

Author: sco1

mlapptools.m

@@ -104,9 +104,12 @@ function fontWeight(uiElement, weight)
             widgetID = mlapptools.getWidgetID(win, mlapptools.getDataTag(uiElement));
         end % getWebElements        
 
-        function [win] = getWebWindow(hUIFig)
+        function [win] = getWebWindow(hUIObj)
             warnState = mlapptools.toggleWarnings('off');
             % Make sure we got a valid handle
+            % Check to make sure we're addressing the parent figure window,
+            % catches the case where the parent is a UIPanel or similar
+            hUIFig = ancestor(hUIObj, 'figure');
             assert(mlapptools.isUIFigure(hUIFig),...
               'mlapptools:getWebWindow:NotUIFigure',...
               'The provided window handle is not of a UIFigure.');