Work started on a different, more complex AST. Need to write tests!

The new grammar needs to be documented.
Remove dual_test.py
Editted the gitignore, to remove clutter.
Remover the unnecessary files
Re-wrote tests

_astgen.py got tests. dual_ast.py has new tests.
Major Changes in Generation of AST nodes from the configuration file

The ast nodes file is now a .cfg. (Edited setup.py for that)
No longer have typed nodes (Python's Dynamic!!, and I never wanted to implement them, wonder how I got the idea).
The sources generated are cleaner.
Better repr.
Now raises errors that are defined in the module.
Better test coverage. (Not as comprehensive as we'd want)
Merge branch 'new_astnodes_syntax'