objimpl.h, pymem.h:  Stop mapping PyMem_{Del, DEL} and PyMem_{Free, FREE}
to PyObject_{Free, FREE} in a release build.  They're aliases for the
system free() now.

_subprocess.c/sp_handle_dealloc():  Since the memory was originally
obtained via PyObject_NEW, it must be released via PyObject_FREE (or
_DEL).

pythonrun.c, tokenizer.c, parsermodule.c:  I lost count of the number of
PyObject vs PyMem mismatches in these -- it's like the specific
function called at each site was picked at random, sometimes even with
memory obtained via PyMem getting released via PyObject.  Changed most
to use PyObject uniformly, since the blobs allocated are predictably
small in most cases, and obmalloc is generally faster than system
mallocs then.

If extension modules in real life prove as sloppy as Python's front
end, we'll have to revert the objimpl.h + pymem.h part of this patch.
Note that no problems will show up in a debug build (all calls still go
thru obmalloc then). Problems will show up only in a release build, most
likely segfaults.

ascii seems like the safest bet that it will exist.  I wonder if utf-8
would be a better choice?  This should get test_fileinput passing on OpenBSD.

(Reported by Jim Jewett.)

(reviewed by Walter Dörwald)

Will backport.

that yields after a throw().  Make @contextmanager not reraise
exceptions, but return a false value in that case instead.  Add test
cases for both behaviors.

string exception was causing a TypeError.

Adds join() and task_done() methods to track when all enqueued tasks have
been gotten and fully processed by daemon consumer threads.

Cleanup terminated processes as well.
Add cmd attribute to Popen4.

Rename file -> filename to be clear.

Will backport.