use Code.abort instead of undefined in auto-generated equations

have MaSh minimize

tweaked signature

strengthened tactic to deal with 'False ==> ...'

made theorem extraction code not delve too far when looking at local fact, by relying on 'strip_thm' instead of (wrongly) reverse-engineering proof terms

improved duplicate detection in "build_name_tables" by ensuring that the earliest occurrence of a duplicate (if it exists) gets picked as the canonical instance

updated S/H docs

use MePo with Auto Sledgehammer, because it's lighter than MaSh and always available

drop only real duplicates, not subsumed facts -- this confuses MaSh

renamed relcomp_def to relcomp_unfold