merges data frames containing all neccessary informations for plotting with PlotOutput()
MergeDf(x, y, y2 = FALSE, y3 = FALSE, legend, legend.y2 = FALSE,
legend.y3 = FALSE)vector containing the x values
vector containing the y values
optional vector containing the values for the second y coordinates
optional vector containing the values for the third y coordinates
name of the y values in the legend
optional name of the second y values in the legend
optional name of the third y values in the legend
data frame with columns containing all above information in equalized length as requested by gglot