Special terms with operator name usually appear in combination with the
name. The current penalties only took name + special term into account
not special term + name.
Fixes#2876.
Additional penalty for special terms with operator None
should only go to near searches. To reduce the number
of produced searches, restrict the none operator to
appear only in conjunction with the name.
Moving the logic for extending the SearchDescription into the
token classes splits up the code and makes it more readable.
More importantly: it allows tokenizer to define custom token
classes in the future.
