Line Plot dialogue is not producing multiple plots for multiple variables

[fagiothree]

Describe the bug
In R-Instat 0.8.0 the Line Plot dialogue is not producing multiple plots for multiple variables, but a single plot

To Reproduce
Steps to reproduce the behaviour (could use any data set). For example

1. Open the ggplot2 data frame in "economics"
2. Click on Describe > Graphs > Line Plot..
3. Select "Multiple variables" and add 2/3 variables to the receiver for y and "year" for x
   
   the output obtained is the following
   

Expected behaviour
We should get a line per variable (graph obtained with the same dialogue in R-Instat 0.7.6

[N-thony]

@fagiothree that is correct, the issue is with code. When you set colour directly in geom_line(), you're specifying a fixed color for all the lines. In the current code, colour="blue" means that all the lines will be blue, regardless of the data. I'm ignoring the reason it has been changed like that. Perhaps @rdstern can explain this or it is just an issue with code that needs to be fixed now.

[Vitalis95]

Thanks @fagiothree for pointing this out, we experience the same issue during Uganda workshop and as @N-thony mentioned, the colour is fixed for all the lines. I think we can remove that part to match how it worked in earlier versions.

[fagiothree]

@N-thony @Vitalis95 I think the problem is not just in the colour, but it is considering all the points as part of the same line, see this graph displaying mean(tmax) and mean(tmin) by year for dodoma

[N-thony]

@N-thony @Vitalis95 I think the problem is not just in the colour, but it is considering all the points as part of the same line, see this graph displaying mean(tmax) and mean(tmin) by year for dodoma

@fagiothree this is what I get when I edit the code from the script window by removing colour = "blue" in geom_line