(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/cargo.t

@@ -0,0 +1,65 @@
+.TH Command CARGO
+.NA cargo "List the commodities on board your ships"
+.LV Basic
+.SY "cargo [<SHIP/FLEET> | <SECTS>]"
+.SY "lcargo [<UNIT/ARMY> | <SECTS>]"
+The cargo command lists the commodities on board your ships 
+in readable format. The lcargo command does the same for land units.
+.s1
+The <SHIP/FLEET>, <UNIT/ARMY>, and <SECTS> arguments are
+provided in case you only wish to look at one ship/unit
+or one fleet/army or all ships/units within a given area.
+.s1
+The report format contains the following fields:
+.s1
+.in \w'ship type\0\0'u
+.L shp#
+the ship number, or
+.L lnd#
+the unit number,
+.L "ship type"
+the type of ship; \*Qpatrol boat\*U, \*Qsubmarine\*U, etc, or
+.L "unit type"
+the type of unit; \*Qwar band\*U, \*Qengineer\*U, etc,
+.L x,y
+the ship/unit's current location (relative to your capital),
+.L flt
+the fleet/army designation letter (set by \*Qfleetadd/army\*U command),
+.L eff
+the ship/unit's efficiency,
+.L sh
+the number of shells on board,
+.L gun
+the number of guns on board
+.L pet
+the amount of petroleum on board
+.L irn
+the amount of iron on board
+.L dst
+the amount of gold dust on board
+.L bar
+the number of gold bars on board
+.L oil
+the amount of oil on board
+.L lcm
+the amount of light construction materials on board
+.L hcm
+the amount of heavy construction materials on board
+.L rad
+the amount of radioactive material on board
+.in
+.s1
+For example:
+.EX cargo K
+.NF
+shp#     ship type      x,y   flt eff   sh gun pet irn dst bar oil lcm hcm rad
+  86 aircraft carrier -29,-51  K  100% 298   4   0   0   0   0   0   0   0   0
+ 110 battleship       -29,-51  K  100% 100   8   0   0   0   0   0   0   0   0
+ 115 battleship       -29,-51  K  100%  60   8   0   0   0   0   0   0   0   0
+ 181 destroyer        -27,-35  K  100%  40   4   0   0   0   0   0   0   0   0
+ 182 destroyer        -27,-35  K  100%  40   4   0   0   0   0   0   0   0   0
+ 183 destroyer        -27,-35  K  100%  40   4   0   0   0   0   0   0   0   0
+6 ships
+.FI
+.s1
+.SA "land, ship, build, march, navigate, load, lload, fleetadd, army, Ships"