Dynloadable runcores

[dukeleto]

Some proposed GSoC projects may require creating new runcores with dynpmcs. Currently that is not possible but from the following conversation on #parrot, it seems that the groundwork is there:

dukeleto> whiteknight: what stands in the way up pluggable runcores right now?
whiteknight>	just hasn't been implemented, to my understanding
                        cotto and chromatic have done all the necessary encapsulation and prettification wok
chromatic> 	We needed pluggable runcores to make the profiling runcore work, but we didn't need 
                        dynloadable runcores so we didn't implement that.
whiteknight>	right, there wasn't a use-case until now

[cotto]

Pluggable runcores remain possible but having them doesn't seem to be either necessary or especially beneficial. If nobody can provide a compelling reason to keep this ticket within the next week or so, I'll consider it safe to reject.