Enable PYMALLOC on release modes as well

I guess it was originally turned on for the extra debugging it provides,
but it also a decent amount faster than system malloc/free
(though I think we could do better still).

from_cpython/Include/Python.h

@@ -20,10 +20,10 @@
 
 #define PYSTON_VERSION "0.5"
 
+#define WITH_PYMALLOC
 // XXX: testing
 #ifndef NDEBUG
 #define Py_REF_DEBUG
-#define WITH_PYMALLOC
 #define PYMALLOC_DEBUG
 // Uncomment this to get some very heavy ref debugging:
 // #define Py_TRACE_REFS