Merge ast-branch to head

This change implements a new bytecode compiler, based on a
transformation of the parse tree to an abstract syntax defined in
Parser/Python.asdl.

The compiler implementation is not complete, but it is in stable
enough shape to run the entire test suite excepting two disabled
tests.

Lib/cgitb.py

@@ -22,6 +22,7 @@ The default handler displays output as HTML.
 """
 
 __author__ = 'Ka-Ping Yee'
+
 __version__ = '$Revision$'
 
 import sys