Scene exception list not updated, Double show names in scene excep list after manual scan

webserve.py: small typo that prevented the absolute "scene absolute" numbering to update in the displayShow page.

scene_exceptions.py: scene exceptions were not saved. the exceptionCache variable used to cache the scene exceptions. The list with exceptions is updated in db, but when reopening your series edit page, the scene exception list is retrieved from the cache instead the db. I've created a small patch that updates the cache after updating the scene exceptions in db.

show_name_helpers.py: After each manual search the showName was added to the scene exceptions list. This was only added to the cache, but was anoying because up until a restart the list with scene exception names kept growing. Fixed this by refering to the function by value instead of by reference.