update up2date

[bbolker]

The up2date() function now has an update_gauss_disp argument which (if TRUE) halves all (?) instances of the betad parameter stored in a glmmTMB object (and its environments). Unlike the rest of the up2date function, this is not idempotent ...

As of 73e0a7f, the $modelInfo component has a $packageVersion component. It would probably make sense to make the default of update_gauss_disp equal to is.null(pv <- obj$modelInfo$packageVersion) (since models created after now will be using the updated SD-parameterization of the Gaussian ...)