Don't abuse WebKit by modifying div#leaderboard every few milliseconds

[y21]

Is your feature request related to a problem? Please describe.
Right now the game sets the inner HTML of div#leaderboard to "" (empty string) and readds all users to it which is very ineffective.

Describe the solution you'd like
Instead it should only update itself if:

1. A blob entered/left the game (would end up in inserting the user into the leaderboard)
2. A blob nommed another one (would change BR of both opponent and blob who nommed)

Describe alternatives you've considered

• Don't remove its content and re-append all child elements but only change the affected blobs.

Additional context
priority: high label because it causes bad devices not being able to play the game (e.g. my Raspberry Pi) because of the lag.

[y21]

Fixed.