Previously the boot image was kept in the separate file "flisp.boot".
This caused all kinds of problems, as bootstrapping is wont to do. The
biggest problem was finding a portable and convenient pathname for it.
Instead of dealing with all that stuff about how to find the file,
just store the image in a huge C string constant that goes into the
main executable. This necessitates adding a C-string hex dumper into
the Lisp system, and making build.sh slightly more complicated, but
that's a small price to pay for not having to carry a separate file
everywhere we go. Also, flmain.c is a lot simpler now and we don't
have to play around with symlinks.
