[tlbuild] asy 1.96 in sources

[Karl Berry]

Asy 1.96 is now in the sources, so please give it a whirl.

John B told me that new features of C++ are being exploited,
specifically std::tr1::shared_ptr, which may require g++-4.3.  Hope it
goes ok.

Vladimir, after you've installed it for {i386,x86_64}-linux, I'll update
the support files.

Thanks,
k