GNU Chess 5 maintenance

[Simon Waters]

Couple of recent issue, such as not building with GCC v4, and comments
from Ethan Burns on protocol compliance have me back digging around in
the code after a longer than expected break (sorry about that).

I intend to modify the program such that it doesn't make unnecessary
chatter when "--xboard" is passed as an option, and that it relies less
on idioms that happen to work with Xboard/Winboard, and complies more
closely with the engine interface as specified by Tim ($Id:
engine-intf.html,v 2.1 2003/10/27 19:21:00 mann Exp $).

Currently I don't plan for any backward compatibility, i.e. any programs
relying on these idioms, rather than merely allowing it, will likely
break with release of 5.08.

The thinking "extension" mentioning in the specification, where GNU
Chess can denote various points in its thinking will remain (at least
till changes in search make it obsolete).

I have 71 emails pending with various bugs, or enhancement features, and
29 relating to documentation issues, most of these will probably not
result in changes as they are duplications or clarifications. Please let
me know if there is anything outstanding you think I may not be aware of.

 Thanks,

 Simon