Prevent console errors for first-time builds

When a build is run the first time, certain objects are not defined
since, well, it is it's first run. Check to ensure the data exists
before traversing the data tree.
Show the last updated time for each build individually
Update build last check time after xhr request is complete
Use setInterval instead of recursive setTimeout
Remove unnecessary <span>
Merge pull request #13 from mattdbridges/gh-pages

Fix errors and display individual build update