Update plot.R - wrong x-Axis label

[kambeitzlab]

No description provided.

[coveralls]

Coverage remained the same at 85.897% when pulling a022e84 on kambeitz:patch-1 into 81509be on jakob-r:master.

[jakob-r]

Hi, thanks for submitting a PR. But I think you got confused. This can be blamed on a bad documentation of the output of the plot. I will look into fixing this.
The x-axis shows indeed the "date of birth". This term is a bit unusual in the field of hyperparameter optimization and originates from the field of evolutionary optimization.
In the plot you don't see which parameter setting was tried but the progress of the optimization over time.
So "Date Of Birth" refers to the optimization iteration in which this setting was evaluated - so in other words the x-axis shows how many hyperparameter settings have been evaluated until then.