Dialog behavior: Create a page layout for ui-dialog using same markup from a ui-page

[scottjehl]

Dialogs can simply be ui-page divs with a different class applied to style them as an overlay. The link that references the dialog can just use either data-transition="pop" or "slideup"... or, we could add a data attribute like data-behavior="overlay" or something, that could use existing transitions in addition to adding the overlay class "ui-dialog" or "ui-overlay" to the loaded page.

Essentially, this would take the place of writing a dialog plugin at all.

The only logic it'd need is to decide if the page is short enough to overlay on the existing page, or if it should go to a new page for scrolling purposes.