Update filter for Firefox 35.0 version bump (#122)

This pull request addresses issue #122, updating the dashboard to support the new release of Firefox, adding 35.0 and 'adding' 31.0 (the new ESR) and preserving 24.0 (the old ESR) for one more cycle before 24 is EOL'd.

Adding @whimboo and @andreieftimie for visibility.