upgrade pre-built libraries for Windows and Mac OS X

Mostly upgrades the drawing stack to the latest Cairo, Pango, Glib,
etc., but also upgrades the OpenSSL library on Windows to 1.0.1g.

The new "racket/src/native-libs" directory provides scripts to
rebuild the libraries from source. Those script are fragile, because
library sources and configuration scripts are fragile. The
scripts at least archive some expertise/advice in a mostly executable
form.
openssl: recognize version 1.0.1g

Merge to v6.0.1
fix `typed/test-engine`