pytypedecl: Allow 'pass' in empty classes. Add optional parameter syntax.
Move '*' handling into the grammar. Constants.

Do '*' processing in the grammar, instead of the tokenizer.
Add (parser) support for constants.
clean up naming

Remove unnecessary "Py" prefixes and "Def" suffixes.
Add comment to typed_tuple.py.
Merge ast.py and typing.py. Call the result "pytd.py".
Added TODOs for sanitizing dangerous eval's
fix shift reduce conflicts in grammar
Make syntax more pythonic, clean up.
Add new node class.

Add namedtuple based class generator "Node", which includes a visitor interface.
Use new Node class instead of namedtuple.

Also, remove typed_tuple.py.
Remove variable arguments. Improve naming.

Rename "ConstType" to "Scalar".
Allow to override the Visit() function on nodes.
cleanups, optional parameters, homogeneous types, add prettyprinting