[CVS ci] PMC-data-5

[Leopold Toetsch]

I have checked in the final changes for putting the ->data member of the 
PMC into the PMC_EXT structure.
This reduces the size of PerlScalars by another sizeof(void *).

- created a new ParrotIO class (only init and destroy yet)
- remove newinterp: use "new Px, .ParrotInterpreter" instead
- fixed a missing end in comp.t
- minor changes to make it run
This feature can be toggled in include/parrot/pobj.h
#define PMC_DATA_IN_EXT 1
(Its turned on currently)
Now we could create custom PMC_EXT structures depending on the class:
Now we have e.g. for an Array or Hash:
  pmc->pmc_ext->list   pmc->pmc_ext->hash
Better would be:
  pmc->pmc_ext_for_list or pmc->pmc_ext_for_hash
This would need (instead of the current pmc_ext_pool) a new unmanaged 
sized pool allocator, which should be quite simple by extending the 
current sized pool functions.

Comments welcome,
leo