Improve generated object handlers

Do more initialisation at module load time.

Use a shared set of handlers for cases when the C/C++ object is
destroyed with free().

Most of the code in the free_obj and create_object handlers is the
same for every wrapped class so factor that out into common functions.

Lib/php/phprun.swg

@@ -206,3 +206,24 @@ static swig_module_info *SWIG_Php_GetModule() {
 static void SWIG_Php_SetModule(swig_module_info *pointer, int module_number) {
   REGISTER_LONG_CONSTANT(const_name, (long) pointer, CONST_CS | CONST_PERSISTENT);
 }
+
+/* Common parts of the "create_object" object handler. */
+static zend_object *SWIG_Php_do_create_object(zend_class_entry *ce, zend_object_handlers *handlers) {
+  swig_object_wrapper *obj = (swig_object_wrapper*)zend_object_alloc(sizeof(swig_object_wrapper), ce);
+  zend_object_std_init(&obj->std, ce);
+  object_properties_init(&obj->std, ce);
+  obj->std.handlers = handlers;
+  obj->newobject = 1;
+  return &obj->std;
+}
+
+/* Common parts of the "free_obj" object handler.
+   Returns void* pointer if the C/C++ object should be destroyed. */
+static void* SWIG_Php_free_obj(zend_object *object) {
+  if (object) {
+    swig_object_wrapper *obj = swig_php_fetch_object(object);
+    zend_object_std_dtor(&obj->std);
+    if (obj->newobject) return obj->ptr;
+  }
+  return NULL;
+}