directly instead of libevent.

Degeneralize the header reading code in cache_http.c which seems to
be cleaner anyway.

An #ifdef at the top of cache_acceptor.c selects which implementation
you want: libevent or kqueue.



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@597 d4fa192b-c00b-0410-8231-f00ffab90ce4