Updated documented CohortParams. Updating the range checking on ouput
from methods in CohortParams.
Finished documenting CohortParams. Cleaned up the code a bit, removing a couple
functions and reworking some code for ease of understanding.
Added an in_range check to utils, which is now used in CohortParams.
Small typo correction
Updated to modern keywords, e.g. != -> not_eq and && -> and