return value of mrb_obj_is_kind_of() should be int (used as boolean); fix #71

include/mruby.h

@@ -406,7 +406,7 @@ const char * mrb_obj_classname(mrb_state *mrb, mrb_value obj);
 struct RClass* mrb_obj_class(mrb_state *mrb, mrb_value obj);
 mrb_value mrb_class_path(mrb_state *mrb, struct RClass *c);
 mrb_value mrb_convert_type(mrb_state *mrb, mrb_value val, mrb_int type, const char *tname, const char *method);
-mrb_int mrb_obj_is_kind_of(mrb_state *mrb, mrb_value obj, struct RClass *c);
+int mrb_obj_is_kind_of(mrb_state *mrb, mrb_value obj, struct RClass *c);
 mrb_value mrb_obj_inspect(mrb_state *mrb, mrb_value self);
 mrb_value mrb_obj_clone(mrb_state *mrb, mrb_value self);
 mrb_value mrb_check_funcall(mrb_state *mrb, mrb_value recv, mrb_sym mid, int argc, mrb_value *argv);