Add the latest stat data to the stat page

When retrieving stat data from the backend, we also need to generate the latest stat data and show it on the stat tab page.

We can consider remove the 'create stat' button after this patch is merged, as the latest stat data will be always retrieved and displayed in the table
Handle StaleElementReferenceError during Selenium testing now that stats graph takes longer to draw
Merge pull request #50 from cloudfoundry-incubator/latest-stat-data

Add the latest stat data to the stat page

I had to add some handling for StaleElementReferenceError's due to the stats graph taking longer to draw.