Add options to set colours of points.

[simonthelwall]

I think at the moment it is not possible to set the colours of the points. This would be a helpful addition

[chrismainey]

There is an option to do this in the development version on GitHub, but not CRAN I don't think. I'm about to release an updated version to CRAN through. the argument you need is plot_cols = c(vector of colours) . It's not a very elegant way to achieve it, but it works for now.