Log Message:
Update to 4.8.1. Changes since 4.8:

* Fixed the reference count handling of a module in the error paths when
  initialising it.
* Added support for (vaguely) defining private assignment operators to
  suppress the generation of PyQt4 assignment helpers.
* Fixed a regression in the creation of new exceptions.
* Various changes (including bumping the major version number of the C API)
  to accomodate the design of the API selection support. The implementation
  should not need any further data structure changes.
* Fixed a code generation bug when an /ArraySize/ argument was typedef'ed.
* Fixed sipResolveTypedef().