Changes for version 0.24
- INCOMPATIBLE CHANGES
- Introduce protocol version which must be specified by all property handlers (assumed to be 1 if unspecified). This is to handle introducing changes at the basic structure of wrapper code which is potentially incompatible with some/lots of existing property handlers.
- Bump protocol version from 1 to 2: to return result immediately, handler must now say 'goto RETURN_RES' instead of 'return $res' directly. This is so that some handlers get the last chance to do something to $res before it is returned.
- Introduce section: 'before_return_res'.