create_model_func: Create model function pointer
In jameshay218/antibodyKinetics: antibodyKinetics

Creaters a function pointer for model_func to save passing multiple vectors constantly. This function will return the same thing, but requires only a vector of (unnamed) parameters and a vector of times providing the parameter vector is the same order as in the given parTab argument. Users should use this function to create the interface function from a single parTab, rather than using model_func each time.

1 2	create_model_func(parTab, exposures, form = "isolated", cross_reactivity = FALSE, typing = FALSE)

`parTab`	the full parameter table - see example csv file
`exposures`	the exposure table - see example csv file
`form`	string to indicate if this uses the "isolated" or "competitive" version of the model
`cross_reactivity`	if TRUE, uses cross reactivity parameters to infer expected titres against heterologous strains
`typing`	if TRUE, uses parameters corresponding to the exposure type rather than exposure index