closes #26; feat: replace weight with count field for queries section in...

closes #26 (closed); feat: replace weight with count field for queries section in scenario, tuned up logic foe this change

It was decided to abandon the weights system, that was being used in scenario, in favor of explicitly specifying the number of a particular query because of problems with rounding via Math.round: at different weights and target queue size, the number of queries in the queue may be more or less than required. If Math.ceil() is used, unnecessary queries will be generated, which leads to unnecessary work on parameter generation and removal of unnecessary queries.