Simplified the implementation of ElementLookupNode and IndirectReferenceNode. None of them now deletes an rbType object when updating. After the DAG is constructed, the rbType Tree cannot be deleted in the general case because its listeners cannot be dealt with correctly under those circumstances. Only downstream listeners are allowed to delete the Tree.
Minor changes to printout of burnin and screenmonitor defaults
Merge branch 'development' of github.com:revbayes/revbayes into development
Fixed a number of merge problems, after pushing of older code to the development branch of the repository.
Merge branch 'development' of github.com:revbayes/revbayes into development