Fix php_v8js_hash_to_jsobj for v8 functions

Currently if a function is returned from JavaScript to PHP context it's converted to a PHP object of V8Function class (ce=php_ce_v8_function).  If this function is passed back to JavaScript normal "object wrapping" takes place which results in JS context seeing an object of type "V8Function"

This patch makes php_v8js_hash_to_jsobj recognize the special class and instead passes back a handle to the original function.

This addresses the second part of @cscott's issue #33