.ui-br class is not defined in theme css file. It is also not defined in jQueryMobile's structure css. But it is there if using the combined 'structure with default theme' css. Tested with both 1.1.0-rc.1 and 1.0.1 structure files.
You're right. It's supposed to live in the theme file not the structure file. I'll make sure to add it in.
Deleted files no longer in use (they've been moved) and fixed issue #81…
… (.ui-br missing)