Construct a simulator for a model

Usage

make_simulator(model.name, scenario.name = NULL, values = NULL, local = FALSE)

model.name: name of the model (see list_models() for options)
scenario.name: Optional. Name of scenario to simulate. See README for model.name for options. If NULL, use base model.
values: Optional. List containing updates to variables + values used to initialize the model simulator. If NULL, use default list is read from disk and used as is.
local: logical. if TRUE, use local model definition (in models subdirectory of main project repo). if FALSE, use package models.