FROM-CYCLES can produce invalid permutations

[Robert Smith]

from-cycles can produce invalid permutations for overlapping cycles, which can e.g. cause to-cycles to not terminate.

PERM> (from-cycles (list (make-cycle 6 7)
                         (make-cycle 2 4 5)
                         (make-cycle 1 9 4 8)))
#<PERM 9 4 3 8 2 7 6 1 4> ; Invalid
PERM> (to-cycles *)
... ; Does not terminate

[Robert Smith]

More robust FROM-CYCLES. Fixed issue #2

→ <<cset dd822687b6a6>>