[CVS ci] use pointer vtables for passing Sub address

[Leopold Toetsch]

I've remove the rather hackish set_integer_native() and get_integer() 
methods for Sub-like PMCs.

The old sequence:

  set_addr I0, _label
  set P0, I0
is now just

  set_addr P0, _label

This might break some languages using such constructs.
Also obtaining the address of a Sub-like PMC is changed, its now:
  get_addr I0, P0

leo