trailing newlines in *.{sml,sig} files from src/ removed

Trailing newlines from SML files in src/ were rendered in HTML documentation.

Get integer self-test to work with Poly/ML.

Implement some improvements to the pre-processing of natural number goals
such that OMEGA can now prove goals of the form
(x MOD c + y MOD c) MOD c = (x + y) MOD c
in reasonable time. Cooper can't, unfortunately, so the test case for the
above (with c = 1001) is added to a new class of examples that are only
tried for Omega.

A fix for the bug reported in hol-info by Arthur van Leeuwen. Also
extended the testing programs to be able to check goals (like the one
he provided as an example).
The problem is that his goal had an assumption where the
non-presburger sub-term was in the scope of a universal quantifier.
(If it was a existential then it could be pulled out, turned into a
universal, stripped, allowing access to the non-presburger sub-term
so that it could be generalised away.) The conversion still doesn't
cope with this situation, but the tactics now won't attempt to include
assumptions that look like that.

Reorganised test programs so that regression suite is shared between
omega and cooper tests. Also added useful Perl program for doing
comparisons between test runs.

New test case for Omega, and slight fiddle with Makefile.

Extended C program for testing decision procedures so that it can be
pointed at arbitrary executables; also made it cope with initialisation
delays (it would kill programs that hadn't properly loaded if they
took longer than the user-mandated delay to do so). Now it won't
start interrupting programs until they've started producing some
output.