issue 74: alternative way to scale heights by 1/2 that works with tip dates as well
issue 74: alternative way to scale heights by 1/2 that works with tip dates as well

tgvaughan/beast2,Anaphory/beast2,tgvaughan/beast2,CompEvol/beast2,tgvaughan/beast2,Anaphory/beast2,Anaphory/beast2,CompEvol/beast2,tgvaughan/beast2,CompEvol/beast2,Anaphory/beast2,CompEvol/beast2