A function for calculating a movement matrix from user specified unfished stock biomass fraction in each area.
Used by simmov to generate movement matrices for an operating model.

`makemov(fracs = c(0.1, 0.2, 0.3, 0.4), prob = c(0.5, 0.8, 0.9, 0.95))`

## Arguments

- fracs
A vector nareas long of fractions of unfished stock biomass in each area

- prob
A vector of the probability of individuals staying in each area or a single value for the mean probability of staying among all areas