(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/power.t

@@ -0,0 +1,89 @@
+.TH Command POWER
+.NA power "Display arbitrarily measured strengths of all countries"
+.LV Basic
+.SY "power [num]"
+.SY "power new [num]"
+.SY "power country <NATS>"
+The power report provides one view of national strengths.
+It can be particularly helpful in planning defense strategies
+and treaty voting.
+.s1
+If the optional \*Qnum\*U argument is given, only the
+top num entries in the power chart will be displayed.  Note that for
+deities, if you give a negative number, only the top num entries in
+the power chart will be displayed, and the power number rating will
+not be displayed.
+.s1
+If the optional \*Qnew\*U argument is given,
+the program will take several minutes to gather information
+and generate a power report based on that up-to-date information.
+This costs several BTU's (typically 10).
+.s1
+If the optional \*Qnew\*U argument is not given,
+the program will shown you the report generated
+the last time someone asked for new data.
+.s1
+If the optional \*Qcountry\*U argument is given, then the information
+is only given for those particular countries.  Countries are
+separated by the "/" character as in:
+.EX power c Fodder/19/Mirky
+Note that countries may be specified as either names or numbers.
+.s1
+In the power report the countries are listed
+in order of decreasing \*Qpower factor\*U,
+each being represented by a line in the following format:
+.s1
+.NF
+sects  eff civ  mil  shell gun pet  iron dust oil  pln ship unit money
+.FI
+
+Each column represents a different commodity or aspect for that country.
+The columns and values used in computing the \*Qpower factor\*U are:
+.NF
+a	# of sectors
+b	average sector efficiency
+c	# of civilians
+d	# of military
+e	# of shells
+f	# of guns
+h	tons of iron ore (not displayed)
+i	tons of gold dust
+j	# of gold bars
+k	tons of food (not displayed)
+l	tanks of oil
+g	# of planes
+m	# of ships
+mm	tons of ships (not displayed)
+r	# of land units
+n	# of dollars
+oo	units of light construction materials (not displayed)
+pp	units of heavy construction materials (not displayed)
+qq	megatons of nuclear weaponry (not displayed)
+bb	gold bars
+.FI
+.s1
+The \*Qpower factor\*U is determined by the following equation:
+.s1
+.NF
+power factor = for each land unit calculate and add the following
+                ((((land unit lcm cost / 10) * (land unit effic / 100)) +
+                  ((land unit hcm cost / 10) * (land unit effic / 100))) * 2)
+power factor += for each ship calculate and add the following:
+                ((((ship lcm cost / 10) * (ship effic / 100)) +
+                  ((ship hcm cost / 10) * (ship effic / 100))) * 2)
+power factor += for each plane calculate and add the following:
+                (20 * (plane effic / 100) * (nation tech level / 500))
+power factor += ((nation money / 100) + (petrol / 500) +
+                 ((civilians + military) / 10) + (shells / 12.5) +
+                 (iron / 100) + (dust / 5) + (oil / 10) + bars +
+                 (guns / 2.5) + (lcms / 10) + (hcms / 5))
+power factor += ((number of sectors * (average sector effic / 100)) * 10)
+power factor = ((power factor) * (nation tech level / 500))
+power factor = ((power factor) * (research factor))
+
+.FI
+.s1
+The research factor is either 1, if RES_POP is not being used, or 1+(max 
+pop in a sector)/10000, if it is being used.
+.s1
+.SA "census, nation, Communication, Nations, Diplomacy"