Calibrated Yule birth rate prior

See Yule birth rate prior, though be aware improper priors on the birth rate is discouraged – use a log-normal instead.

Also, be aware that there is some unpredictable interaction between the calibrated Yule prior and calibrations, so always run an MCMC sampling from the prior and inspect the tree height distribution in tracer to be sure it is reasonable. If the distribution is not what you expect, adjust the birth rate prior till the prior distribution of the root height is satisfactory.