feat(Utils): return a mean time step from .GetFeatModel

Refs #106

R/Utils.R

@@ -54,7 +54,13 @@
                            daily   =       1 * 24,
                            monthly =   28:31 * 24,
                            yearly  = 365:366 * 24)
-    res$TimeStep <- res$TimeStep * 3600
+    res$TimeStepMean <- switch(res$TimeUnit,
+                               hourly  =             1,
+                               daily   =             1 * 24,
+                               monthly = 365.2425 / 12 * 24,
+                               yearly  =      365.2425 * 24)
+    res$TimeStep     <- res$TimeStep * 3600
+    res$TimeStepMean <- res$TimeStepMean * 3600
     res$Class <- c(res$TimeUnit, res$Class)
     if (grepl("CemaNeige", res$NameFunMod)) {
       res$Class <- c(res$Class, "CemaNeige")