Get developers/genUseScript to build again

Remove unicode-grep from developers/Holmakefile

Fix developers tools to compile under Moscow ML

Implement unicode-grep as SML program

This avoids variation in the behaviour of the command-line tool, and
should also make the check (self-test in src/portableML/testsrc) work on
Windows.

Fix dependencies for genUseScript in developers/

Tool to generate use-scripts for early HOL

For example,

developers/genUseScript --hol src/bool/boolScript.sml > usethis.ML
poly --use usethis.ML

sets up an interactive session with all of the kernel up to but not
including boolScript.sml (no pretty-printing enabled, or other
interactive niceties though).

Remove more invocations of poly in favour of POLYC

In the developers directory and the building of the help system's tools.

Get comparelogs developer tool to build with Poly

Drop dependency on mlton

Get Moscow ML building of developers/generateBuildSummary to work.

Fix mosml dependencies in src/0.

Even pure signatures depend on the basis2002 module.

Try to make generateBuildSummary buildable under Moscow ML too.

New tools to generate regression test reports.

Update the tool for analysing logs that are created during the build
process. Provide mlton and mosml based versions. Also experiment on
the way with overriding mosml's old TextIO with a Basis97 version.

Update makefile, and adjust comparelogs to allow for dispensing with
prettinesses.

Program to "analyse" multiple log files where "analyse" equals "print out
prettily"