Minor edits
Merge branch 'development' of github.com:revbayes/revbayes into development
Fixed incorrect keepMe action in Rev language DAG nodes, copied from RevBayesCore::DeterministicNode. Cleaned up ls() function.
Fixed problem with type spec of Simplex not inheriting from ModelVector<RealPos>, causing problems with type checking and argument matching.
Cleaned up debug code, and slightly modified printing of models and formatting of ls() output.
Merged with development branch on origin