Set a max-width on crumbs just in case

Summary: Ref D17361. This sets a reasonable width on crumbs just in case a title is super long. Also fixes a weird Safari issue.

Test Plan:
Set a username to "hector" and check Safari. Create a badge named "MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM" and test length.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17472