[Melbourne-pm] Memoize subroutine annotations

[Toby Corkindale]

Memoize is useful, but having to specify routines seems a bit backwards.
ie.
   sub my_subroutine { .. do stuff .. }
   memoize('my_subroutine');

Luckily, you can enable a method annotation instead, with 
Attribute::Memoize:

ie.
   sub my_subroutine :Memoize { .. do stuff .. }


tjc