New AST definition.
Update the AST with comments of the mailing list.
Remove polymorphics_arg, it's just a type_name list. Update the comments.
Add constructors for operator, constant and rule.
Change operator structure in the AST.
Updated matching algorithm for the new ast
Modify the AST following the remarks. Non-mutable AST. Type application.
Update ast.mli
Added term example for the lambda-calculus
Update symbols.ml according to new AST.
Simplified the error generation.
Some corrections in the error generation.
Modify the kind, is just a list of Atom-Type as suggested by Roven, the checks will be performed at another step.
Minor modifications of the system error. Move files into data/error.
starting implementation of the new ast in the parser
Parser updated with the new ast and include system fixed
Change the layout of the project.
Remove unused test file.
Rename file check the rewriting AST.
Move ast.mli to rewriting_ast.mli.