gam_natural_vec: Convert working parameters to a vector of natural parameters
In simonecollier/lizardHMM: Fitting Lizard Movement Data with HMMs

This funciton converts the vecgtor of working parameters to a vector of natural parameters not inculding delta.

gam_natural_vec(
  num_states,
  num_variables,
  num_subjects,
  num_covariates,
  working_params,
  state_dep_dist_pooled = FALSE
)

`num_states`	The number of states in the desired HMM.
`num_variables`	The number of variables in the data.
`num_subjects`	The number of subjects/trials that generated the data.
`num_covariates`	The number of covariates in the data that the transition probability matrix depends on.
`working_params`	A vector of the working gamma parameters for the HMM.
`state_dep_dist_pooled`	A logical variable indiacting whether the state dependent distribution parameters `alpha` and `theta` should be treated as equal for all subjects.