feature request: href and target properties for tab

[christophe-g]

Buttons and list-items have href and target properties, which allow them to be real links. That's great and solve an long-standing issue (#441).

Is there any chance to add those properties (and implement similar behavior) to tab so that it is easier to bind navigation state with tab-bar and tab active state, as it is often the case in SPA/client router context ?