[MERGE] wordlist refactoring

Hi all,
    this patch is an attempt at streamlining the wordlist implementation
in 3.HEAD, by:
- OO-izing it [1]
- providing an unit-test for it
- giving it a couple of convenience functions
- documenting it

It's still a work-in-progress, but in the end a wordlist would probably
be better implemented by using a set of Strings anyways.
It's however a step forward already, since it gives wordlist callers
better c++ semantics than the current implementation in HEAD.

The patch has been compile-tested, unit-tested, test-suite'd and
run-tested.

Please review and hopefully apply.

   Kinkie