Improve docs for iolist_to_binary
Add Path.relative_to_cwd and rely on it when generating stacktraces
Clean up and expose are more complete API in Exception
Handle unsafe vars inside or/and
Add missing helpers file
do_justify should be private
Merge pull request #1600 from devinus/defp-justify

do_justify should be private
Macro.to_string handles access and kw-lists nicer