obsoleting annotate level 2

[Nick Roberts]

 > Thus, while level one annotations are only a small maintenance burden,
 > level two annotations are.  Even if Emacs had been using level two
 > annotations for years, we would be trying to get rid of them.

A possible further reason for keeping level one annotations is that, like
GDB/MI, it is really a machine interface (that is the output is intended to
be read by a program). 

How about renaming it GDB/MI level 0 ;-)

Nick