[bug 939305] Australis Tour Updates for Firefox 29.0 release

Updated `/firstrun` and `/whatsnew` tour pages for 29.0 release. Both pages feature a funnel cake test (for en-US users only).

`/firefox/29.0/whatsnew/?f=30` [no tour]
`/firefox/29.0/whatsnew/?f=31` [tour]

`/firefox/29.0/firstrun/?f=30` [no tour]
`/firefox/29.0/firstrun/?f=31` [tour]

Non en-US locales always get the tour.

Also: Users with Firefox Sync enabled will only see the 'Web We Want' promo on the post-tour landing page. Users without Sync enabled will also see the Sync promo (which will be the vast majority of users).