pad: 
 - some file renaming to be more consistent with my C (and C++) parser
 - some merge of files into one file (for lexer and test_parsing_java)
 - some estetic change in ast_java, and grammar, group in big categories
   ast elements like statement, expression, etc and add cosmetic separators.
 - more grouping, move stuff in xxx_opt, list_opt, avoid intruduce
   intermediate rules that are referenced only once (inline instead)
 - add comments and set of tokens, as done in my other parsers
 - add parse_info for all tokens
 - put in lowercase the grammar rule, so better see what is a token and 
   what is a rule, and what is a OCaml constructor, 
   and make the grammer more like my other grammars.
 - add the wrap for top big categories
 - estet: align actions in grammar
 - move parsing helper functions from ast_java to grammar
 - add the wrap for ident
 - visitor, comment_annotater
 - move type and constructors from ast_java to parser.mly as it's used only
   in intermediate parsing


add the wrap2




