This patch implements MI '-list-target-groups --available' -- for
native linux and remote targets. In both cases, the command actually
returns the list of processes. The bulk of  the patch was written by 
Pedro, I've just added MI bits to it.

The information about processes is passed from target via XML, using new
'osdata' target object with 'processes' annex. The data returned looks
like this:

	<osdata type=\"processes\">
		<item>
			<column name="pid">1</column>
			<column name="user">root</column>
			<column name="command">/sbin/init</column>
		</item>
	</osdata>

This representation is fairly open-ended -- new information can be added 
without changing DTD or parser.  Right now, only bare essentials are provided,
and '-list-target-groups --available' will print just those.

Of course, this flexibility will lead to problems later -- frontend is unlikely
to nicely present an arbitrary set of columns target may report. So in future,
we might need to add up some more detailed specification what data target
may report, and how it will advertise that this data is available, and how MI
should show that data, and how frontend should display that. However, that problem
is general "OS-awareness" thing, and this patch allows the frontend to pick
a process to attach to.

Comments?

- Volodya


It's also slightly under-specified -- I
don't really know how a frontend can make use of any extra information about
processes unless it knows about specific new columns that will be avai