[RFA 1/2] minor Python doc updates

[Eli Zaretskii]

> From: Tom Tromey <tromey@redhat.com>
> Date: Fri, 26 Apr 2013 13:04:29 -0600
> 
> Doug pointed out on irc that the Python docs don't mention the
> close-on-exec change, even though Python was a major driver for the
> approach taken in the patch.
> 
> I also noticed that the docs don't mention SIGINT and SIGCHLD, and
> this is something that has bitten users in the past.
> 
> This patch pulls in some introductory text from the old archer python
> branch that I thought was useful, moves the stdout information to the
> "Basic Python" node, and documents close-on-exec and signal handling a
> bit.
> 
> Ok?

Yes, thanks.

> +You can get quick online help for @value{GDBN}'s Python API by issuing
> +the command @w{@kbd{python help (gdb)}}.

This dumps about 20 screen-fulls (each screen 57 lines) on my system.
Shouldn't this be paginated?  This part:

> +At startup, @value{GDBN} overrides Python's @code{sys.stdout} and
> +@code{sys.stderr} to print using @value{GDBN}'s output-paging streams.

seems to imply it should, but it doesn't here (MS-Windows), at least
not with GDB 7.6 and Python 2.6.6.