(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/sinfrastructure.t

@@ -0,0 +1,61 @@
+.TH Command SINFRASTRUCTURE
+.NA sinfrastructure "Report infrastructure of sectors"
+.LV Basic
+.SY "sinfrastructure <SECTS>"
+The sinfrastructure command displays specific infrastructure information on
+some or all of the sectors you occupy.
+.s1
+In the syntax of the census command
+<SECTS> is the area on which you wish information,
+(see \*Qinfo syntax\*U).
+.s1
+A typical usage might be:
+.EX sinfrastructure 0:9,0:9 ?des=m
+which would list data for mines in an area
+to the south-east of the capital.
+.s1
+A sinfrastructure lists each of your sectors in the specified area headed by:
+.NF
+Thu Aug  8 08:37:03 1996
+                      road        rail       defense
+  sect        eff   eff mcost   eff mcost   eff  fact
+.FI
+These columns represent:
+.s1
+.in \w'defense fact\0\0'u
+.L sect
+the x and y coordinates of the sector
+.L eff
+the efficiency of the sector (affects all benefits
+of a designated sector except mobility and defense)
+.L "road eff"
+the road efficiency of the sector
+.L "road mcost"
+the mcost used to determine the mobility cost of moving things and marching
+non-train units through the sector
+.L "rail eff"
+the rail efficiency of the sector
+.L "rail mcost"
+the mcost used to determine the mobility cost of moving trains through the
+sector.  If the rail eff is 0, trains cannot move through this sector.
+.L "defense eff"
+the defense efficiency of the sector. 
+.L "defense fact"
+the defense factor of the sector.  This is how well the sector defends.
+All sectors start at 1, and improve (see "improve") from there to the maximum
+shown in "show sect stats"
+.in
+.s1
+For example:
+.EX sinf #0
+.NF
+Thu Aug  8 08:37:03 1996
+                      road        rail       defense
+  sect        eff   eff mcost   eff mcost   eff  fact
+   1,-1   f    0%    0% 0.400    0% 0.400    6%  1.18
+   0,0    c  100%    2% 0.192   28% 0.113    8%  1.08
+   2,0    m  100%    0% 0.200    0% 0.200  100%  2.00
+3 sectors
+.FI
+.s1
+.SA "improve, census, commodity, resource, Sectors, Infrastructure, Mobility, Commodities"