[Patch] Allow __sleep to return NULL

I've attached a patch (both for HEAD and the PHP_5_3 branch) that allows the magic __sleep() method to return NULL to continue the normal serialization process (all members are serialized). This allows the __sleep() method to do meaningful cleanup without having to resort to Reflection overhead. The patch retains the original behavior (E_NOTICE) if anything other than an array or NULL is returned from the function. I check the results of a "make test" on the PHP_5_3 branch with and without the patch. I skipped the results from HEAD because there were so many unrelated failures it was pointless. The one additional failure in 5.3 with the patch is actually a reverse unit test. I've included a patch (separately, because it's the same for HEAD and PHP_5_3) to correct the expected result from this test. Thanks, Andrew

Attachment: [text/x-patch] andrewm.sleep_null.53.patch
Attachment: [text/x-patch] andrewm.sleep_null.HEAD.patch
Attachment: [text/x-patch] andrewm.sleep_null.test.patch