Add alternative redirect's behavior when user is '~'
This is a new feature to create generic URL's related to usernames in Noosfero. It is useful for internal links on articles and for general links on themes.
- If you're logged in as "test" and you go to /~/blog it will redirect you to /test/blog
- If you're logged in as "test" and you go to /myprofile/~ it will redirect you to /myprofile/test
- If you're not logged in and you go to /profile/~ or any other link using "~" it will give you a not found page(404).