* Change generic arithmetic primitives to be trampolines into some

* Change generic arithmetic primitives to be trampolines into some
procedures that are stored in the fixed objects vector.  This permits
some upwards compatibility of new R4RS arithmetic and gives the
compiler a method for invoking the binary arithmetic operators which
are normally not available in the global environment.  It also
provides a solution to the problem of making generic arithmetic
available during the cold load.  The compiled-code interface bypasses
the primitive interface and directly applies these trampolines, thus
avoiding the overhead of the interface when the trampoline is also
compiled.

* Increase the default constant size of the regular band to 400, and
the heap size of the compiler band to 1000.