Load right stream with Show More on mobile

  - Load aspects stream if user is on this stream instead of loading the
    activity stream
Code style + allow aspects to be nil

  - Only use old hash style
  - Don't replace the aspect ids list with an empty array if it's nil
Test returned path for Show More on mobile

  - Added test when the currant page is Aspects Stream
  - Modified test for the Stream page to account for the new possibility
    (i.e current page is Aspects Stream)
Merge pull request #5002 from taratatach/4999-show-more-in-mobile-aspects-stream-redirects-to-my-activity

Load right stream with Show More on mobile
Home page, registration page and robots.txt personnalization
Add my aspects link in the header