(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/nmap.t

@@ -0,0 +1,65 @@
+.TH Command NMAP
+.NA nmap "Generate a map showing new sector types, seas, etc"
+.LV Basic
+.SY "map <SECTS | SHIP> <s|p|l|*|h>"
+.SY "nmap <SECTS | SHIP> <s|p|l|*|h>"
+.SY "smap <SECTS | SHIP> <s|p|l|*|h>"
+.SY "lmap <SECTS | SHIP> <s|p|l|*|h>"
+.SY "pmap <SECTS | SHIP> <s|p|l|*|h>"
+A map gives you a graphic representation of all or part of your country.
+.s1
+Your own sectors as well as sea, mountains, wasteland and unowned
+wilderness and plains show up as a designation mnemonic (see
+\*QSector-types\*U).  Other sectors appear as question marks
+(\*Q?\*U).
+.s1
+Examples:
+.EX map -9:18,-8:5
+generates a 28 x 14 map based on data supplied by the sectors
+in the area specified.
+.NF
+    ---------0000000000111111111
+    9876543210123456789012345678
+ -8        . . . - -             -8
+ -7       . . . . - ^            -7
+ -6    . . . . - - - -           -6
+ -5   . . - . a a - ^ ? ? -      -5
+ -4  . . . . k o ! - ^ ? ? ?     -4
+ -3 . - . a h j a ^ ^ ^ ^ ^ -    -3
+ -2  . . - . a a a ^ a a - - -   -2
+ -1   . . . a a a b + + ^ ^ -    -1
+  0  . . . m c u a a - ^ - ^     0
+  1   . - . a a . a a - - ^      1
+  2    - ^ ^ a a a ^ a - - ^     2
+  3     - - - - - - - . . -      3
+  4      ^ - - - - - ^ - -       4
+  5       - ^ - - ^ - - -        5
+    ---------0000000000111111111
+    9876543210123456789012345678
+.FI
+.s1
+.EX map # >mapfil
+where your \*Qrealm\*U (or '#',
+see \*Qinfo realm\*U or \*Qinfo update\*U)
+is -5:5,-6:6 will type out a 11 by 13 sector map
+and also put the map in the file called \*Qmapfil\*U.
+.s1
+Also, if you give a ship # instead of coordinates or a realm, map
+will show you a small realm around the given ship (assuming you
+own it).
+.s1
+If you use nmap, you can get a map that shows new sector designations
+instead of old sector designations of your own country.
+.s1
+If you use lmap, you can get a map around a land unit, 
+instead. Pmap does the same for a plane. Smap does
+the same for a ship.
+.s1
+.L "MAP FLAGS"
+.s1
+If you give an 's' flag, all your ships will be shown on the map.
+An 'l' flag does the same for land units, and a 'p' for planes.
+\&'*' shows all in this order: land units, ships, planes.
+To highlight sectors you own, specifiy the 'h' flag.
+.s1
+.SA "census, commodity, radar, realm, route, update, Maps"