PackfileAnnotation: Add PMC and type methods
PackfileAnnotation: Add PMC and type methods

Previously there was no way to determine the type of the annotation
(except trial and error), nor a way to get a PMC annotation.

tkob/parrot,youprofit/parrot,FROGGS/parrot,youprofit/parrot,youprofit/parrot,tkob/parrot,FROGGS/parrot,FROGGS/parrot,parrot/parrot,youprofit/parrot,tkob/parrot,parrot/parrot,tkob/parrot,FROGGS/parrot,youprofit/parrot,FROGGS/parrot,FROGGS/parrot,FROGGS/parrot,tkob/parrot,tkob/parrot,youprofit/parrot,tkob/parrot,parrot/parrot,tkob/parrot,FROGGS/parrot,youprofit/parrot,parrot/parrot,parrot/parrot,youprofit/parrot