New assembler

I've been writing a new assembler, which is now integrated with
movitz. This replaces the assembler in the ia-x86 package and CVS
module, so this no longer has to be loaded at all. The new assembler
is considerably leaner and meaner, and I think more than doubles
compilation speed.

The new assembler resides in movitz/asm.lisp (architecture independent
code) and movitz/asm-x86.lisp. The latter implements (dis)assembly of
x86 instructions in 16, 32, and 64-bit mode. 64-bit mode has not been
used or tested much yet, and probably contains some bugs. It should be
possible to hook in some asm-foo.lisp, although to get movitz going
you'd need a new compiler-foo.lisp etc. also.

-- 
Frode Vatvedt Fjeld