Merge pull request #400 from tzz/master

cf-sketch.pl: add standalone_inputs runfile subkey
Merge pull request #401 from tzz/master

cf-sketch.pl: add header runfile subkey
sudoers: fix parameter types
Merge pull request #405 from tzz/bugfix/sudoers

sudoers: fix parameter types
run_once: new sketch to run a command once in a given context