lexer: fix `EOF::parser_index` generation.

Signed-off-by: Jean Privat <jean@pryen.org>
grammar: split `expr_atom` into `expr_single`

This new priority class enable args without parentheses in
one-line annotation.

Signed-off-by: Jean Privat <jean@pryen.org>
grammar: enable single parentheses-less arguments in one-line annotations

~~~
fun foo is some_annot "hello"
~~~

Signed-off-by: Jean Privat <jean@pryen.org>
grammar: remove old-style syntax for attributes

* no more `var _foo`
* no more `readable` and `writable` as reserved keywords

Signed-off-by: Jean Privat <jean@pryen.org>
grammar: unify method syntax

Only one APropdef subclass for method: AMethPropdef

Specific method definitions are with annotations:

* new annotation `abstract` (still a keyword because `abstract class`)
* activate annotation `extern` (till a keyword because `extern class`)
* intern is no more a reserved keyword

Signed-off-by: Jean Privat <jean@pryen.org>
grammar: new power operator `**` (starstar)

~~~
var a = 2 ** 3 ** 4
~~~

Not yet implemented in the lib because a regeneration of c_src is needed

Signed-off-by: Jean Privat <jean@pryen.org>
parser: regenerate the parser

Signed-off-by: Jean Privat <jean@pryen.org>
src: remove classes and nodes related to the old syntax

Signed-off-by: Jean Privat <jean@pryen.org>
nitx: remove unused methods `AAttrPropdef::*_accessor`

Signed-off-by: Jean Privat <jean@pryen.org>
nitpreyty: remove the oldstyle syntax, there is still some fixme to fix

Signed-off-by: Jean Privat <jean@pryen.org>
tests: update some AST-related sav/*.res files for tools

Signed-off-by: Jean Privat <jean@pryen.org>
Merge: Kill old syntax

Grammar is simplified and parser regenerated.

Changes

* one-line annotations can have a single argument without parentheses
* no more old-style attribute declaration
* no more intern, readable and writable as reserved keyword (they are identifiers now)
* intern, extern and abstract are genuine annotations for AMethPropdef
* no more zoo for AMethPropdef subclasses
* Bonus, introduce the power operation `**` (not implemented yet, but parsed)

TODO: see what is broken in nitpretty

Pull-Request: #756
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>