'before', 'after', and 'silent' keys.

Although this is still a work-in-progress, Tracker now has basic
support for the ‘before’ and ‘after’ keywords. For example, if someone
uses ‘/tr before 5m after 3d’, the argument parser and TimeLexer’s
automatic time-frame correction would make this equal to ‘/tr -t 3d,5m’.

There’s also support for a new ‘silent’ keyword. Although this breaks
away from the tradition of having keywords only represent parameters,
there’s no free character to represent ‘silent’ or any of its synonyms
and antonyms.

I also have to implement support for it in more places, but for now,
it’s available in the rollback command and the ‘q’ flag can be used in
place of the keyword in the apply and dismiss commands.

AND I FINALLY DID SOMETHING WITH THE WORLDOPTIONS CLASS! :D