Added optional history.pushState behaviour to Tab.show.

[Robadob]

history.pushState updates the browser history and address bar.

I found it unusual that the functionality of pressing tabs updating the address bar to this url was unavailable, so that tabs could be more easily treated as a single page nav. I understand this behaviour isn't always necessary, hence the optional usage by adding follow-url as an attribute to the anchor which is used to show the tab.

Loading the correct tab then works something like this where all tab anchors have .my_tabs

$(document).ready(function(){
    $address=document.URL;
    if($address.replace(/^[^#]*/, "").length==0)
       $address=$address+$(".my_tabs.active").attr("href");
    $selector = $address.replace(/^[^#]*/, "");
    $(".phase_link").each(
        function( index ) {
            if ($selector == $(this).attr("href"))
                $(this).tab("show");
        }
    );
});

history.pushState is HTML5 so wont work in older browsers, however this functionality is implemented at the end of the show method so any javascript error caused by it would't break the primary functionality of tabs. If it were desired for this to implemented for older browsers this stackoverflow post suggests a method which I haven't tested; http://stackoverflow.com/a/136506/1646387

[Robadob]

I fixed the only reported Travis issue, I won't try and rebase the change because I tried to do it on an earlier version and just ended up creating 2 more commits.

[cvrebert]

Given the outcome of #581, I'm doubtful that this will be merged.

[Robadob]

Ah thanks, given heruan's comment on that pull request towards ie7 support being dropped in BS3 there's always a change that this functionality will be looked at in future, so a possible implementation is here if it is.

[fat]

don't really think this is worth adding. it's super easy to add for people that want it: listen to shown.bs.tab – and my hunch is it would mean a lots of support down the line. If you really want this behavior… you're probably better off building ontop of a framework that manages url structure for you