Changes since version 1.2.1

Fix: sometimes new customizations could not be properly created.
Fix: improved background management of customizations.
Fix: improved how thumbnails are displayed and generated.
Fix: fixed an incompatibility with PyObjC applications.
Added: moved SurfRabbit Help under the SurfRabbit menu instead of the application's Help menu.
Added: improved and simplified how custom CSS codes are applied to customized pages.
Added: added viewing support for OmniWeb 5.5.
Added: improved how dynamic content is handled when customizing.