grow: Estimates actual growth given performance, other covariates,...
In evanchildress/wbPersist:

Estimates actual growth given performance, other covariates, and parameters

1	grow(pars, river, startLength, flow, biomass, performance)

`pars`	Matrix of betas from growth model
`river`	Vector of river locations for individuals
`startLength`	Vector of starting lengths
`flow`	Vector of mean flow for the growth period
`biomass`	Vector of brook trout biomass during the growth period
`performance`	Vector of growth performance from the `getGrowthPerformance()`