Allow chained sequences with closures
and more than one element after last infix:<...> operator
RT #123303 fix exception throwing of undeducable sequences
Optimization of chained sequences with closures
FROGSS++; this is closer to the original version;
still passes tests from RT #123329
Merge branch 'nom' into newio
move List.ACCEPTS Parcel and Array for now

List.ACCEPTS now indicates a success status.
set $/ on listy match too
fake up .from/.to on List for lists of matches
Merge branch 'nom' into newio
Merge pull request #336 from usev6/nom

Allow chained sequences with closures
Expose some MOP primitives for Perl 6 programmers.

Now the 6model API has been stable for a while, we should expose some
key aspects of it. So far, short of using nqp::ops, it has not been
possible for a Perl 6 meta-programmer to totally create their own
kinds of type from scratch; customizing existing ones has been the
only way. Custom publishing of method caches has also not been on
offer, and some modules could certainly make use of it. Now it will
be possible.
Fix missing decont with .REPR implementation.
Run S12-meta/primitives.t.
Merge branch 'nom' into newio