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.
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 0775bb8..d9f1337 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -15,7 +15,7 @@
 */
 
 #include "Python.h"
-#include "compile.h"
+#include "code.h"
 #include "frameobject.h"
 #include "eval.h"