Added a truly stand-alone engine in boosthost.

Along with it, now the library is built according to a true
automated bootstrapping process. It is not complete yet, but
Base.oz, Init.oz and the OPI are fully bootstrapped.
Excluded the boot Base.ozf from the distribution.

Now Init.oz gives its Base as an argument to the functions
generated by the bootcompiler. This means that, as soon as we
have a compiled Init.ozf that contains the compiled Base
module, we do not need Base.ozf anymore.
Fixed a compile error with some compilers.