(info, html): Implement.

(all): Depend on info.

Flatten info directory.  This undoes the move to one subdirectory per
chapter, which was done during Empire 2.  The structure doesn't buy us
much, as the info name space is flat, and it complicates makefiles.

Overhaul info.pl:
- It now wants to run in the root of the build tree.
- Information on source files and subjects is now stored in makefiles,
  thus info.pl no longer picks up random junk from the file system.
- Clean up Perl anachronisms, in particular use subroutine arguments and
  results rather than global variables where convenient.
- Change format of diagnostics to the common format used by GNU tools,
  so that Emacs and the like can parse it.
- Catch missing .SA.
- When creating a new subject file, cowardly refuse to overwrite an
  existing file.
- Subject files contain topics sorted by chapter, then by name.  The
  order of chapters used to depend on how Perl sorts hash keys.  Fix
  it.

info/announce.t

@@ -0,0 +1,31 @@
+.TH Command ANNOUNCE
+.NA announce "Send an announcement to all players"
+.LV Basic
+.SY "announce"
+The announce command is a variant of the telegram command.
+It sends your message to \fIall\fR of the players in the game.
+This convenient service may cost money to provide, depending on
+your deity.
+.s1
+For example:
+.EX announce
+.NF
+Enter telegram for everybody
+undo last line with ~u, print with ~p, abort with ~q, end with ^D or .
+1024 left: 
+1023 left:               For Immediate Release
+ 987 left:                     from
+ 962 left:                 Groonland Embassy
+ 928 left: 
+ 927 left: 
+ 926 left: HELP!  Curmudgeon just TRASHED our capital!  We had even proposed
+ 860 left: a very fair treaty, but they did it anyway!  People of the World,
+ 794 left: UNITE!  Overthrow the slave masters of Curmudgeon!
+ 744 left: .
+JoeBlowLand is rejecting your announcements
+ZappaLand is rejecting your announcements
+.FI
+.s1
+Note that announcements can be rejected. See info reject for more information.
+.s1
+.SA "pray, wire, telegram, read, reject, Communication"