Implement Parcel.rotate

One wonders whether the internal logic would warrant an nqp::rotate op, which
could then be shared with List.rotate
Turn "with no arguments" to "without arguments"
Further awesomize CHECK error message, jnthn++ for suggesting
Make Parcel.reverse return a Parcel rather than a List
Remove some obsolete postcircumfix[] code
Some more obsolete method postcircumfix {} removal
Add "is DEPRECATED" as an Attribute trait (for now, so I can make todo tests)
Add "is DEPRECATED" trait to class/etc. (to be able to add todo tests)
Merge remote-tracking branch 'origin/nom' into unified-build