Main ss3sim functions and a description of their purpose.

Simulations can be run through the run_ss3sim function, which then calls the change functions. Users can control what the change functions do through a series of plain-text case files. For example, the case ID d1 corresponds to the case files lcomp1, agecomp1, and index1, as described in the table. Users can also skip setting up case files and specify arguments to ss3sim_base directly, or use the change functions as part of their own simulation structure (see the vignette).