Make sure Supply.rotor handles different threads
Make sure Supply.batch handles different threads
Code esthetics: make Supply parameter $s
Oops, Parcels are immutable
First stab at implementing Supply.live
nice error if $?CLASS isn't there around signatures
Make sure Routine.perl makes an EVALable string

E.g. (sub {1+1}).perl would produce something like
'sub() { #`(Sub|4345502344) ... }', which will parse sub() as a
function.  This fixes Routine.perl to be more like
'sub () { #`(Sub|4345502344) ... }'.
Supply.unchanged -> Supply.stable (to match spec)
Implement Supply.delay
Implement .Supply coercer
Adapt S17 tests to reorganized structure
Test all of the S17-supply separate test files
Add 2012/day(16|19) tests
Make sure .Supply on a Supply is a noop
Supply.delay: done/quit are also delayed

Thanks to timotimo++ for reminding me
Add Supply.Promise, channeling from jnthn++
Migrate methods from SupplyOperations to Supply

Many of these are not creating inner classes that "does Supply", so they can
live inside the Supply role proper, thereby eliminating a layer of indirection.
Esthetics: $s -> $source, :source($s) -> :$source
Add noop handling to Supply.(stable|delay)
Add testing of Supply.delay