[ESS] bindings to str and object

[Martin Maechler]

Just a quick feedback 
as long as you are making proposals for key maps:

  C-c [letter]

is "not allowed" to be bound by (x)emacs packages.
These are reserved for ``user's own binding''.

But I think it's a good idea to use another ``prefix'' binding
(a key sequence that starts a whole keymap) for things like
``mouse-me''.

BTW:  C-c C-c in auctex is *not* a prefix binding.
      It is a simple key binding to a ``smart command''
      (actually to a command with as smart default).

Martin