Rc0: tabIcon no longer allows space in name (font awesome)

Using font awesome classes is now broken with rc0, after the upgrade from beta. For example, the value tabIcon=“fa fa-sitemap” no longer works. The following error, complaining about the space in the class names, is generated:

error_handler.js:45 EXCEPTION: Error in ./Tabs class Tabs - inline template:0:239 caused by: Failed to execute ‘add’ on ‘DOMTokenList’: The token provided (‘ion-md-fa fa-sitemap’) contains HTML space characters, which are not valid in tokens.

It works fine for icons with no spaces in the class name. I believe this is a bug.