(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/Research.t

@@ -0,0 +1,37 @@
+.TH Concept Research
+.NA Research "How Research level is calculated each update"
+.LV Expert
+.sp
+.s1
+If the RES_POP option is in use, 
+the research level of a country determines the maximum number of civilians,
+mil, and uw's
+that can live in a sector. For ordinary sectors, the maximum is:
+.s1
+.ti 3
+min(999, 400 + 600 * ((research*4 + 50)/(research*3 + 200)))
+.s1
+So, for example, at 0 research, after an update, the max you
+could have in a sector would be 550 civs, 550 uws, and 550 mil.
+Note that in the case of captured sectors,
+the research level of the current owner governs, even if the old
+owner of the sector had a higher/lower research.
+.s1
+If, after population growth, there are more civs than the limit, the
+excess are lost. Uw's & mil work the same way, each being individually
+limited.
+.s1
+The research level also affects the likelihood of plague outbreaks.
+(Unless the NO_PLAGUE option is used, of course)
+.s1
+The \*Qnation\*U command will display,
+among other things,
+your current research level.
+.s1
+The procedure determining how much your research level goes up every
+update is exactly the same for research as it is for technology
+(see "info Technology") except for the fact that "research log base"
+is always 2.00 and "easy research" is always 0.75.  But besides this,
+research bleeds, decays, and leaks in exactly the same way as technology.
+.s1
+.SA "Innards, nation, Products, Technology, Nations, Producing, Updates"