[PATCH] Vector refactor, part 2

Hi,
  attached is the second part of Vector refactoring. It replaces
Vector with std::vector in all clients except for Stack, which I
believe to more sensible to replace with std::stack instead of
reimplementing.
Code has been farm-build-tested and run-tested. The patch is big
because it has lots of context; feature branch is at
lp:~squid/squid/vector-refactor

-- 
    Kinkie