[0/2] more OO, Ada exception catchpoints: intro

[Pedro Alves <pedro@codesourcery.com>]

Continuing the catchpoints OO theme, Ada catchpoints are
mostly implemented in ada-lang.c, except for the corresponding
commands' themselves implementation, plus a couple of other
helpers.  In this mini-series, that builds on top of 
the series starting at
<http://sourceware.org/ml/gdb-patches/2011-06/msg00269.html>:

 - patch #1 moves the implementation and registration
   of the "catch exception/assert" commands to ada-lang.c.

 - patch #2 switches Ada catchpoints to the OO scheme
   similar to how other catchpoints have been converted in
   my previous series, and removes most of the knowledge about
   Ada catchpoints out of breakpoint.c (serving as proof/excuse
   for me to add a few more bits to breakpoint_ops and export
   a few functions from breakpoint.c :-) ).  The main benefit from
   the change, apart from making the code/design cleaner (IMO), is
   that this lifts the limitation that Ada catchpoints can't have
   user specified conditions.

(I think it might be nice even to move the whole bunch to
its own file (ada-lang.c is pretty big itself) afterwards,
though I'm not planning on doing that myself.)

No regressions on x86_64-linux (with an Ada runtime with debug info,
so that Ada catchpoints work).

Joel, WDYT?  Okay to apply?

(let me know if you'd like a combined patch make it
easier to test on your end)

-- 
Pedro Alves