Foundation 5 topbar syntax correction

[Ivan Polchenko]

_navigation.html.haml:
...
%nav.top-bar{:data-topbar => true}
...

results in:
"undefined local variable or method `topbar'" error.

changing
%nav.top-bar{:data-topbar => true}
to
%nav.top-bar{"data-topbar" => true}

fixes that.

[Daniel Kehoe]

Thanks for catching this. I'll fix it in the next release.