[RFC] some doubtable MMDs?

[Leopold Toetsch]

I'm not quite sure, but it seems that some of the MMD functions may 
better be vtable methods:

- bitwise_sh[rl]*    shift by anything other then int?
- bitwise_lsr        is missing generally
or even just a plain opcode only:
- logical_{or,and,xor}  return a PMC depending on the boolean value
What are HLLs expecting of these infix operations?
OTOH it might be useful that the current get_<type>_keyed operations 
(postcircumfix:[]) become MMD subroutines:

  Px = Py[Pz]    Pz = String, Int, Key, Slice, ...
Comments welcome,
leo