View progress as an individual or as a team (or your alt accounts)

[piyush33patel]

Key changes:

1. Select tag having options as Individual(default) and Team.
2. When selected 'Individual', has the original functionality.
3. When selected 'Team', user has to enter the usernames(user-handles) of the team members separated by commas.
4. The team ratings is calculated as mentioned in: https://codeforces.com/blog/entry/16986
5. The rating calculation of unrated and negatively rated accounts is not well handled, but it should not effect any functionality.