[th02/zuninit] Initial state

AKA "the source of the infamous STOP message".

This is pretty much irreducible assembly code, so it may very well be that we
don't even touch this file ever again, but at least it completes our build.
[th03/zunsp] Initial state

This one contains 4 instructions (on lines 462, 528, 534 and 1309,
respectively) for which TASM chooses different opcodes than the original
compiler.