Added loadDashboard external API method

Ok - I hope I'm not wearing you guys out with pull requests ;-)

I wrapped the logic that loads the initial state of the dashboard into a function called loadDashboard and also exposed that as an external api to the dashboardOptions.  My motivation was the ability to be able to roll back the dashboard to the previously saved state without forcing the user to do a full page refresh.  I didn't add this into the default set of buttons, but I did document the fact this method is available.  

Let me know what you think.