[racket] Embedded Racket 5.1.3 on Windows

One problem with Racket for Fluxus seems to be that
MZ_REGISTER_STATIC() works only after scheme_basic_env() is called. I
see why MZ_REGISTER_STATIC() is broken when places are enabled, and
I'll work on that.

Meanwhile, if you move the call to Interpreter::Register() to just
after scheme_basic_env(), like this:

	m_Scheme=scheme_basic_env();
	Interpreter::Register();

does it work?