Open list people who like/saw post in popup window
Fine tune feed details view

- Rename "In this discussion" box to "Top Participants" and only show top 3 users who join the discussion
- Reduce "Seen by" list to last 5 users
Bugfix: "People who saw this" popup sometimes does not show full list of users who saw the post
Hide the "Add to Contacts" button on "People who like/saw this" popup if user is viewer
Bugfix: Multiple photo attachments are displayed incorrectly
Bugfix: Can't download attachments
Fine tune sign up and sign in page
Fix broken footer links (about, privacy, terms, jobs)
Bugfix: forgot password form does not work properly
Merge branch 'feature/forgot_password' into develop
Bugfix: selenium tests fail randomly