with PyObject_CallFunctionObjArgs, which is 30% faster.

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.

 - IMPORT_NAME takes an extra argument from the stack: the relativeness of
   the import. Only passed to __import__ when it's not -1.

 - __import__() takes an optional 5th argument for the same thing; it
   __defaults to -1 (old semantics: try relative, then absolute)

 - 'from . import name' imports name (be it module or regular attribute)
   from the current module's *package*. Likewise, 'from .module import name'
   will import name from a sibling to the current module.

 - Importing from outside a package is not allowed; 'from . import sys' in a
   toplevel module will not work, nor will 'from .. import sys' in a
   (single-level) package.

 - 'from __future__ import absolute_import' will turn on the new semantics
   for import and from-import: imports will be absolute, except for
   from-import with dots.

Includes tests for regular imports and importhooks, parser changes and a
NEWS item, but no compiler-package changes or documentation changes.