ARIA live region attributes are added to the Undo component in markup, causing them to be incorrect on Firefox 2

In the Undo component, we create an ARIA live region like this, directly in the markup:

var markup = "<span class='flc-undo' aria-live='polite' aria-relevant='all'>" +
"<span class='flc-undo-undoContainer'><a href='#' class='flc-undo-undoControl'>undo</a></span>" +
"<span class='flc-undo-redoContainer'><a href='#' class='flc-undo-redoControl'>redo</a></span>" +
"</span>";

This markup is hard-baked to the newer Firefox 3-style syntax, which causes it not to work in Firefox 2. The unit tests also fail on Firefox 2 as a result.

We should always add ARIA attributes using jQuery rather than directly in markup, since it does this normalization for us.

Note that we're no longer formally testing against Firefox 2, so this isn't a huge deal but is something we should try to fix if we can find the time.