#' Creation of the RunOptions object required to the RunModel functions.
#'
#' Users wanting to use FUN_MOD functions that are not included in
#' the package must create their own RunOptions object accordingly.
#'
#' ##### Initialisation options #####
#'
#' The model initialisation options can either be set to a default configuration or be defined by the user.
#'
#' This is done via three vectors: \cr \emph{IndPeriod_WarmUp}, \emph{IniStates}, \emph{IniResLevels}. \cr
#' A default configuration is used for initialisation if these vectors are not defined.
#'
#' (1) Default initialisation options:
#'
#' \itemize{
#' \item \emph{IndPeriod_WarmUp} default setting ensures a one-year warm-up using the time-steps preceding the \emph{IndPeriod_Run}.
#' The actual length of this warm-up might be shorter depending on data availability (no missing value being allowed on model input series).
#'
#' \item \emph{IniStates} and \emph{IniResLevels} are automatically set to initialise all the model states at 0, except for the production and routing stores which are initialised at 50\% of their capacity. This initialisation is made at the very beginning of the model call (i.e. at the beginning of \emph{IndPeriod_WarmUp} or at the beginning of IndPeriod_Run if the warm-up period is disabled).
#' }
#'
#' (2) Customisation of initialisation options:
#'
#' \itemize{
#' \item \emph{IndPeriod_WarmUp} can be used to specify the indices of the warm-up period (within the time-series prepared in InputsModel). \cr
#' - remark 1: for most common cases, indices corresponding to one or several years preceding \emph{IndPeriod_Run} are used (e.g. \emph{IndPeriod_WarmUp <- 1000:1365} and \emph{IndPeriod_Run <- 1366:5000)}. \cr
#' However, it is also possible to perform a long-term initialisation if other indices than the warm-up ones are set in \emph{IndPeriod_WarmUp} (e.g. \emph{IndPeriod_WarmUp <- c( 1:5000 , 1:5000 , 1:5000 ,1000:1365 )}). \cr
#' - remark 2: it is also possible to completely disable the warm-up period when using \emph{IndPeriod_WarmUp <- 0}.
#'
#' \item \emph{IniStates} and \emph{IniResLevels} can be used to specify the initial model states. \cr
#' - remark 1: if \emph{IniStates} is used, all model states must be provided (e.g. 60 floats [mm] are required for GR4J, GR5J and GR6J; 60+2*NLayers floats [mm] are required for CemaNeigeGR4J, CemaNeigeGR5J and CemaNeigeGR6J; see fortran source code for details). \cr
#' - remark 2: in addition to \emph{IniStates}, \emph{IniResLevels} allows to set the filling rate of the production and routing stores for the GR models. For instance for GR4J, GR5J and GR6J: \emph{IniResLevels <- c(0.3,0.5)} should be used to obtain initial fillings of 30\% and 50\% for the production and routing stores, respectively. \emph{IniResLevels} is optional and can only be used if \emph{IniStates} is also defined (the state values corresponding to these two stores in \emph{IniStates} are not used in such case). \cr \cr
#' @param FUN_MOD [function] hydrological model function (e.g. RunModel_GR4J, RunModel_CemaNeigeGR4J)
#' @param InputsModel [object of class \emph{InputsModel}] see \code{\link{CreateInputsModel}} for details
#' @param IndPeriod_WarmUp (optional) [numeric] index of period to be used for the model warm-up [-]
#' @param IndPeriod_Run [numeric] index of period to be used for the model run [-]
#' @param IniStates (optional) [numeric] vector of initial model states [mm]
#' @param IniResLevels (optional) [numeric] vector of initial filling rates for production and routing stores (2 values between 0 and 1) [-]
#' @param Outputs_Cal (optional) [character] vector giving the outputs needed for the calibration \cr (e.g. c("Qsim")), the least outputs the fastest the calibration
#' @param RunSnowModule (optional) [boolean] option indicating whether CemaNeige should be activated, default=TRUE
#' @param MeanAnSolidPrecip (optional) [numeric] vector giving the annual mean of average solid precipitation for each layer (computed from InputsModel if not defined) [mm/y]
#' @param quiet (optional) [boolean] boolean indicating if the function is run in quiet mode or not, default=FALSE
