Made Buf.subbuf act more like Str.substr
Style nit
Rework of Bag, allowing bags of bags
Slight optimization in pick/roll, much more is needed
Fail on invalid values, rather than die
Make KeyBag work according to spec (mostly) + additional fixes/tweaks
Code esthetics on set() and bag()
Set/Bag are no longer Iterable, Any (implicitely so)

This solves the problem of sets/bags being flattened at most places
There is no keybag() specced
Need to override Set/KeySet
Force leap-second data to be a constant Parcel.

Should save a little bit of time, since now it's just a constant
table lookup.
This test needs ICU on Parrot.
Merge branch 'Buf-subbuf' of https://github.com/dagurval/rakudo into nom
Fix to handle changed behaviour of bag()
Remove superfluous stub (already stubbed in core_prologue)
Add a crude IO::Socket(::INET) port to JVM, add to build
Unbust recv() and read(), a bit
Merge jvm socket code into main impl and fix bugs
Bump NQP_REVISION to get sockets.
Refactor of Set/Bag using roles, jnthn++ for gdb support