[Various] obsoleting the annotate level 2 interface

[Arnaud Charlet]

As one of the GVD (see http://libre.act-europe.fr/gvd) developers, I
confirm that to use the GDB/MI, we are waiting for a stabilized interface
(amny things have changed til recently in MI), and the ability to
support the command line interface for providing a regular gdb console.

Without these two critical points addressed by MI, there is no way we can
replace annotate 1 by MI.

Arno