Setting RM blessed versions of autoconf/libtool/swig/apr/apr-util/httpd/neon/zlib for 1.5

Current situation from tools/dist/construct-rolling-environment.sh:

autoconf-2.59
libtool-1.5.22
swig-1.3.25

apr-0.9.12
apr-util-0.9.12
httpd-2.0.58
neon-0.25.5
zlib-1.2.3

First, tool versions: I propose that we update to the latest release of
autoconf, libtool and swig. We will, of course, be doing beta releases,
and can roll back if issues surface. That means:

    autoconf-2.61 (17-Nov-2006)
    libtool-1.5.24 (26-Jun-2007)
    swig-1.3.31 (20-Nov-2006)

Second, dependency versions:

* It has been suggested that we switch to apr 1.2.x in the dependency
tarball. Do we have consensus on that?

* Does anyone know why we get apr* for the windows source by taking the
versions from the windows httpd source? Do we still need to do that?

* Which Neon series are we going with for 1.5, neon 0.26, or neon 0.27 ?

Max.