Fix OCaml language support

Various improvements:

- character support
- type variable
- polymorphic variant tag
- module name/variant constructor
- support ' in identifier
- add support for literals () [] [||]
- better support for numbers
- remove unrelated rules (from F# maybe?)
- add new ! keywords
- cleanup built-in types

A step backward: remove very incomplete type definition matching

Add tests B)
Adding Mickael Delahaye to AUTHORS.*