Complete REAME.md
Add all microcodes separated by version (includes duplicates)
Add auxiliary references to recover the microcode.

These are from my third try at trying to find out how the microcode was
compiled. These microcodes are used in the stable version of dynamips.
Add disassembly of ppc32_microcode.

Copied from the dev/microcode branch of dynamips.

Heavy on comments, the aim was to produce an equivalent microcode.
The contents look equivalent according to objdump output.
It contains lots of debug info which I haven't tried to remove.

The next challenge is to try and make a C source microcode.