killed most "no_atp", to make Sledgehammer more complete

doc fixes suggested by Andreas L.

make sure that registered code equations are actually equations

accept very long lines in MaSh

make sure add: doesn't add duplicates, and works for [no_atp] facts

no fact subsumption -- this only confuses later code, e.g. 'add:'

generate a comment storing the goal nickname in "learn_prover"

clarified message

added thread-safety warnings

avoid confusion between outer ifs and inner ifs, that caused tactic to go berserk

handle nested tuples in 'let's

more exercises

also unfold let (_, _) = ... syntax

added helper function (that solves chicken-and-egg problem w.r.t. "callssss")

graceful handling of abort

generalized interface

choose facts to reprove more randomly, to avoid getting stuck with impossible problems at first

thread the goal through instead of relying on unreliable (possibly fake) state

added comment

tuning

verbose minimization when learning from ATP proofs

if slicing is disabled, pick the maximum number of facts, not the number of facts in the last slice

if slicing is disabled, don't enforce last slice's "max_facts", but rather the maximum "max_facts"

fast track -- avoid domain error in 0 case

remove overloading of "max_facts" -- it already controls the number of facts passed to ATPs for 'learn_prover'

merged

tuned exercises

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

have MaSh minimize

tweaked signature