postfix-prefix branch ready for merge

I'm done turning most cases of postfix increment/decrement operators
into prefix form.
Most are trivial integers or pointers, thus probably there will be not
much of a difference. A few ones were iterators, where it probably
will make a (small) difference. A few cases were causing (at least to
me) readability issues.
Along the way I've turned a few int-as-bool useages into proper bools;
sorry for the slight feature-creep.

Code builds, tests and runs, I've used as my personal forward-proxy
with no noticeable issues.
It's available at lp:~kinkie/squid/prefix-postfix

If there's no objections, I'd merge.

-- 
    /kinkie