added option to prevent node height adjustment for fixed sampled ancestor trees
added option to prevent node height adjustment for fixed sampled ancestor trees

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