An attempt at porting Rubinius' marshal

Let's experiment and see whether we can port parts of Rubinius'
implementation of stdlib. Let's start with marshal.

bin/from_rubinius.rb performs a simplistic regexp-based translation of
Rubinius to Topaz::Rubinius. The replacement of __instance_variables__ is
a temporary hack which can be removed once Kernel.instance_variables is
available.

lib-ruby/openssl.rb defines some empty OpenSSL classes and a single method
just to make marshal's specs compilable.

lib-topaz/{immediate,marshal,marshal19}.rb are results of translating
respective files from Rubinius using from_rubinius.rb. marshal.rb required
a small change in Marshal.dump due to a parsing issue described in #799.

lib-topaz/topaz/rubinius.rb contains naive, incomplete or simply incorrect
implementations of classes in the Rubinius hierarchy.