Allow '@', '.', '+', and '-' in url names for users
Merge pull request #774 from ahinz/fix/allow-periods-in-username

Allow '@', '.', '+', and '-' in url names for users
Use more permissive url pattern (allow @.+=) for user profile.

PR #774 addressed this for the instance-level urls which redirect to the
site-wide user profile, but missed the urls for the site-wide user profile.