Added a new round type called penalty-round. It works in the following way
1) Any user receives a percent of the task solved based on the number of submissions and elapsed time since the beginning of the contest.
2) By default a user looses 1% of his score every 2 minutes(can be changed)
3) A user looses 3% of his score per additional submission(can be changed)
4) For a solved task a user can not receive less than 50%(can be changed)

The rest depends on the task configuration.