[mod] merge rules for further refactoring and bug fixing
[mod] indent
[enh] big commit: uniformise call/def arguments

* key name is renamed to target
* target now points to a dict, not a string anymore
* old name/target string are converted to name tokens
* def_argument_tuple has disappeared, now a def_argument gets a tuple in
  the target key
* what was def_argument in def_argument_tuple list is now always a name
  token
[mod] fix indent