deprecation warning P0, P1

[Leopold Toetsch]

Due to adaptions to pdd03 the direct access to the return continuation 
is deprecated.

Instead these constructs should be used:
1) PIR code
* return from a sub
   .return()
   .return(foo)
   .return (foo, bar, baz)
   ...
* get the current continuation (for call/cc)
   .include "interpinfo.pasm"
    .local pmc cont
    cont = interpinfo .INTERPINFO_CURRENT_CONT
  The returned continuation is already a real continuation, thus it 
doesn't need cloning any more.

* get the current sub
    .local pmc sub
    sub = interpinfo .INTERPINFO_CURRENT_SUB
2) PASM code
* return from a sub
    returncc  [ proposed opcode, TBD ]
* get the current continuation / sub
   .include "interpinfo.pasm"
    interpinfo Px, .INTERPINFO_CURRENT_CONT    # or _SUB
leo