Some shifting in candidate order to make searching easier
Make sure that [*]:(kv|p|k) pass on their values
Simplify {*}:(kv|p|k|v) to self.(kv|pairs|keys|values)

as the value specified doesn't really matter in this case, and it is the same
as the zen-slice logic.
change $*CWD and $*TMPDIR to IO::Path objects
 by request from dagurval++ and S16 spec