Instead of just checking that hy2py outputs a nonempty string and doesn't crash, we check that a hy2py-generated Python program works the same as the original Hy program.
This test suggests my plan to make hy2py output real Python has succeeded, so I updated NEWS accordingly.
This commit adds -E support for Hy. Similar to Python, hy will ignore
all PYTHON* environment variables, e.g. PYTHONPATH and PYTHONHOME,
that might be set.
Python Class AST expects a body which is a list of ast.Expr. Force
every entry to be stored as a statement. This means we'll preserve
print statements.
Python also doesn't construct docstrings in classes by setting a
__doc__ attribute, it does it by inspecting the first ast.Expr node of
the class. But this means we can remove the special handler for it.
