Vladimir Marangozov's long-awaited malloc restructuring.

For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.

(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode.  I'm also holding back on his
change to main.c, which seems unnecessary to me.)

Python/compile.c

@@ -112,7 +112,7 @@ code_dealloc(co)
 	Py_XDECREF(co->co_filename);
 	Py_XDECREF(co->co_name);
 	Py_XDECREF(co->co_lnotab);
-	PyMem_DEL(co);
+	PyObject_DEL(co);
 }
 
 static PyObject *