misc cleanup of auto_solve and quickcheck:
tools are in src/Tools and loaded uniformly in HOL;
preferences are configured in their proper place -- despite old misleading comments in the source;
use predefined preferences categories;
setmp preferences in-place;
(* Title: Pure/ProofGeneral/ROOT.ML
Author: David Aspinall
Proof General interface for Isabelle, both the traditional Emacs version,
and PGIP experiments.
*)
use "pgip_types.ML";
use "pgml.ML";
use "pgip_markup.ML";
use "pgip_input.ML";
use "pgip_output.ML";
use "pgip.ML";
use "pgip_isabelle.ML";
use "preferences.ML";
use "pgip_parser.ML";
use "pgip_tests.ML";
use "proof_general_pgip.ML";
use "proof_general_emacs.ML";