New interesting demo available

[MJS@mjs.us]

I've refactored one of my apps to take advantage of the new back button functionality.  With PostRedirectGet = prgEnabled it seems to mostly work but for two issues:

1. RegisterCallBack functions fail if invoked after a back button, forward button sequence.  They will only work again after a full refresh.
   
2. Back / forward history gets lost after a bootstrap modal dialog popup (pure bootstrap, no IW bootstrap components).  Not worried about this one so much.
   

I'll provide a demo for issue 1 after some more research.  I have a strong interest in seeing this new functionality work 100% as IW back button behavior always requires an explanation to the customer.  If this gets implemented 100% it would be the 3rd best all-time enhancement of IW in my opinion.

* Start the application. F9 to start a browser session
* MainForm is shown. Press button [Go to SecondForm]
* SecondForm is shown with correct url. Now press the browser back button.
* MainForm is shown. Press 'Callback' button
* The IWEdit1 text is not updated.
* Press F5 for full refresh, 'Callback' button works and IWEdit1 text is updated.