Plot branches connected correctly by `plot_daisie_data`

[Richèl Bilderbeek]

When I plot islands, I get pictures like this:

It could be that the Pull Requests that are pending (#67 and #69) are causing this.

After both are accepted, maybe I should fix this, maybe this Issue can closed...

[Richèl Bilderbeek]

plot_daisie_data is definitely invalid, as the vertical lines branches are in their pre-reverse state:

[Richèl Bilderbeek]

It seems that daisie_data$branching_times now holds the time in 'time before present' (instead of: time after island coming into existence). This means that all results of min and max are now under suspicion 🧐

[Richèl Bilderbeek]

The only change needed to make the vertical lines be correct:

[Richèl Bilderbeek]

Fix colonisation times, highlighting the only change:

[Richèl Bilderbeek]

Fixed!