MAP tree prints correct branch lengths, NexusWriter no longer adds extra
semicolon (which is part of the Newick string)
Add support for root age to SSBDP (w Sebastian)
Correct FNPR to fail gracefully when brothers.size()==0 (arises for
non-ultrametric trees). Corrected w Sebastian
branchScoreDistance function
Corrected two small errors in BSD
add BSD to workspace
Merge branch 'development' of github.com:revbayes/revbayes into development