[Dart] Dashboard rollover times.

[Brad King]

> This is what I do to check server changes.  I grab the submitted XML
> files from public for say VTK. So I tar up Dashboard/(todays
> datestamp)/*.xml and Sites/*/*/(todays datestamp)*/XML/*.xml
Okay, everything seems to be working.  I have merged the changes into the
main tree.  I then updated public's Dart and re-rolled all the dashboards
by hand to make sure they stayed unchanged (and they did).  I created
symlinks to help the yesterday links work across the two encodings.

Clients do not need to update, but they probably should just to keep
things consistent.

-Brad