Adding 1-2-3 claim flow with breadcrumbs.
Screen 3 (share) is currently inaccessible because we can't detect when
the user is done sending their badge to the backpack.
Add simple share page with very boring tweet link
Makes the addQueryString filter more robust and return a SafeString
so the result isn't autoescaped.

Uses addQueryString in send to backpack button redirect, and use
setTimeout which makes Safari happy.
Make double-action on form submit work in IE8
Change commenting of addQueryString
Move claim breadcrumbs to a macro as per suggestion
Change claim wording to claim/collect/show
Merge pull request #41 from stenington/36-claim-flow

claim 1-2-3 flow