Automatically refresh ecogrid sources (endpoints) once per Kepler
Now that there are two ways in which to refresh the available Ecogrid services (as registered in the registry), the refresh should only happen once per Kepler window.
Currently the autorefresh will happen once for each Kepler window when the user selects the Data tab.
Since there has been a lot of time devoted to making startup quick, the refresh should not slow down the start up of Kepler.
And, of course, the user can always manually refresh the sources with the "Refresh" button that is found on the sources tab.