connect error

comma expression in listpop() that was being returned.  Still essentially
unused (as it is meant to be), but now the compiler thinks it is worth
*something* by having it incremented.

- fix broken assert statement; should just raise

have differing refcount semantics.  If anyone sees a prettier way to
acheive the same ends, then please go for it.

I think this is the first time I've ever used Py_XINCREF.

(or to whatever the 'insert' method chose to return).

must have annoyed me at some point.

* Fixes an incorrect variable in a PyDict_CheckExact.
* Allow general mapping locals arguments for the execfile() function
  and exec statement.
* Add tests.

"@ seems the syntax that everybody can hate equally"
Implementation by Mark Russell, from SF #979728.

after a failed import.

This is the last checkin in the "change import failure semantics" series.

    test_failing_import_sticks -- if an import raises an exception,
        ensure that trying to import it again continues raising exceptions
    test_failing_reload -- if a module loads OK, but a reload raises an
        exception, ensure that the module is still in sys.modules, and
        that its __dict__ reflects as much of the reload attempt as
        succeeded.  That doesn't seem like sane semantics, but it is
        backward-compatible semantics <wink>.

getting left beyind in sys.modules.

PyImport_ReloadModule():  restore the module to sys.modules in error cases.
load_package():  semantic-neutral refactoring from an earlier stab at
                 this patch; giving it a common error exit made the code
                 easier to follow, so retaining that part.
_RemoveModule():  new little utility to delete a key from sys.modules.

in failure cases, incompletely initalized module objects are no longer
left behind in sys.modules.

already correct, so not changed here.

Backport candidate.

Backport candidate.

of no more than 8 elements cannot fail.

listpop():  Take advantage of that its calls to list_resize() and
list_ass_slice() can't fail.  This is assert'ed in a debug build now, but
in an icky way.  That is, you can't say:

	assert(some_call() >= 0);

because then some_call() won't occur at all in a release build.  So it
has to be a big pile of #ifdefs on Py_DEBUG (yuck), or the pleasant:

        status = some_call();
        assert(status >= 0);

But in that case, compilers may whine in a release build, because status
appears unused then.  I'm not certain the ugly trick I used here will
convince all compilers to shut up about status (status is always "used" now,
as the first (ignored) clause in a comma expression).