Resolve "Add warm-up period simulated flows in OutputsModel"

Closes #123 (closed)

vignettes/V05_sd_model.Rmd

 ---
-title: "Simulating a reservoir with semi-distributed GR4J model"
+title: "Simulated vs observed upstream flows in calibration of semi-distributed GR4J model"
 author: "David Dorchies"
 bibliography: V00_airgr_ref.bib
 output: rmarkdown::html_vignette
 vignette: >
   %\VignetteEngine{knitr::rmarkdown}
-  %\VignetteIndexEntry{Simulating a reservoir with semi-distributed GR4J model}
+  %\VignetteIndexEntry{Simulated vs observed upstream flows in calibration of semi-distributed GR4J model}
   %\VignetteEncoding{UTF-8}
 ---