Label assignments (v := e) as (* OK *) in src/metis

These labels are my judgement that the references are strictly local
and so not a concurrency issue. Additionally, some assignments in
comments (to Moscow ML specific quietdec, for example) have just been
deleted.

Implement more of Basis2002 for Moscow ML (adding Vector, Array,
ArraySlice and VectorSlice), simplifying what Poly/ML has to emulate.
Haven't done full rebuild test, but have got as far as integerTheory
and Omega, which makes heavy uses of Vector etc.

Latest version of METIS_TAC.

The biggest change is that scheduling provers is done by number of
inferences, not time used, so METIS_TAC is now completely
deterministic. If it works for you on a subgoal, it will work every
time HOL4 is built.

New version of Metis:

+ Uses finite models to guide clause selection in resolution.
+ A Metis test for when HOL is compiled using MLton.

Version 1.3: 17 June 2002

Goals submitted to MESON_TAC when HOL is built .......... 1953
Proved by MESON_TAC ..................................... 1953
Proved by METIS_TAC within 10s .......................... 1946

Between Versions 1.2 and 1.3

* Implemention of definitional CNF to reduce blow-up in number of
clauses (usually caused by nested boolean equivalences).
* Resolution is more robust and efficient, and includes an option
(off by default) for clauses to inherit ordering constraints.