gitweb: Add gitweb(1) manpage for gitweb itself

Most of what is in gitweb.txt it has been pulled directly from the
README and INSTALL files of gitweb.

Current version is somewhat based on structure of SVN::Web manpage
(one of web interfaces for Subversion).

gitweb.conf(5) i.e. gitweb configuration manpage now refers to
appropriate sections in gitweb(1).  gitweb/README now refers to
gitweb/INSTALL and gitweb(1) manpage.  gitweb/INSTALL now refers to
gitweb.conf(5) and gitweb(1).

Inspired-by: Drew Northup <drew.northup@maine.edu>
Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/Makefile

@@ -1,7 +1,7 @@
 MAN1_TXT= \
 	$(filter-out $(addsuffix .txt, $(ARTICLES) $(SP_ARTICLES)), \
 		$(wildcard git-*.txt)) \
-	gitk.txt git.txt
+	gitk.txt gitweb.txt git.txt
 MAN5_TXT=gitattributes.txt gitignore.txt gitmodules.txt githooks.txt \
 	gitrepository-layout.txt gitweb.conf.txt
 MAN7_TXT=gitcli.txt gittutorial.txt gittutorial-2.txt \

Documentation/gitweb.conf.txt

@@ -35,6 +35,10 @@ CGI script with the default name 'gitweb_config.perl' -- allowing
 one to have multiple gitweb instances with different configurations by
 the use of symlinks.
 
+Note that some configuration can be controlled on per-repository rather than
+gitweb-wide basis: see "Per-repository gitweb configuration" subsection on
+linkgit:gitweb[1] manpage.
+
 
 DISCUSSION
 ----------
@@ -109,6 +113,8 @@ Location of repositories
 The configuration variables described below control how gitweb finds
 git repositories, and how repositories are displayed and accessed.
 
+See also "Repositories" and later subsections in linkgit:gitweb[1] manpage.
+
 $projectroot::
 	Absolute filesystem path which will be prepended to project path;
 	the path to repository is `$projectroot/$project`.  Set to
@@ -193,6 +199,9 @@ our $export_ok = "git-daemon-export-ok";
 ----------------------------------------------------------------------------
 +
 If not set (default), it means that this feature is disabled.
++
+See also more involved example in "Controlling access to git repositories"
+subsection on linkgit:gitweb[1] manpage.
 
 $strict_export::
 	Only allow viewing of repositories also shown on the overview page.