[Dart] Trivial Cosmetic Suggestion

[Brad King]

> I tend to agree with that (especially on laptops), these buttons use
> only a very small portion of the vertical space compared to the
> average length of the VTK dashboard. They could easily be fit
> horizontally. The "Powered by Dart" icon is more problematic but it
> could be moved on the right side of the top blue area ("Changes...").
I also would agree with this change.  Most of the dashboard is arranged as
wide rows of information.  The same could apply to the links currently on
the left.

I was also thinking that the logo for the project in the upper left could
be setup as a link to the project's homepage instead of back to the
dashboard.

-Brad