validity check for "bonus" settings in the configuration

[babaknaderi]

The value of "quantity_hits_more_than" should be updated per each study. It is recommended to use a number close to 50% of HITs.
The master script should check out the values of "allowed_max_hit_in_project" and "quantity_hits_more_than" from the configuration file to make sure that they make sense (are in range depending to the study) and show a warning message if not.