* add GetElementRectangle to get element rectangle by element id
* handle case for GetElementRectangle
* add ScrollToElement to scroll HtmlPanel to specific element by id
* fix GetAttributeAt not working for some elements (images/frames)
* update version to 1.4.12.0
* add ILMerge for build
* update demo app to run in .net 2.0
* build demo app into a single exe (embed dll using ILMerge)