docs: Use README.md to generate mainpage with doxygen

Actually we are using a slightly modified one that removes the
`Table of Contents` section and replaces it with the doxygen-compatible
`[TOC]` to auto-generate a TOC that has working links.

Makefile.am

diff --git a/Makefile.am b/Makefile.am
index 7da967d..f44a6bc 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -25,4 +25,7 @@
 	rm -rf docs/html
 	doxygen doxygen.cfg
 
-docs: doxygen.cfg docs/html
+docs/README.doxygen.md: README.md
+	awk '/\#\# Table of Contents/{while(getline && $$0 != ""){}{print "[TOC]"}}1' README.md > $@
+
+docs: doxygen.cfg docs/README.doxygen.md docs/html

doxygen.cfg.in

diff --git a/doxygen.cfg.in b/doxygen.cfg.in
index 8c77b8f..7aa54e8 100644
--- a/doxygen.cfg.in
+++ b/doxygen.cfg.in
@@ -521,7 +521,8 @@
 # directories like "/usr/src/myproject". Separate the files or directories 
 # with spaces.
 
-INPUT                  = include/plist/plist.h
+INPUT                  = include/plist/plist.h \
+			docs/README.doxygen.md
 
 # This tag can be used to specify the character encoding of the source files 
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is 
@@ -625,6 +626,13 @@
 
 FILTER_SOURCE_FILES    = NO
 
+# If the USE_MDFILE_AS_MAINPAGE tag refers to the name of a markdown file that
+# is part of the input, its contents will be placed on the main page
+# (index.html). This can be useful if you have a project on for instance GitHub
+# and want to reuse the introduction page also for the doxygen output.
+
+USE_MDFILE_AS_MAINPAGE = docs/README.doxygen.md
+
 #---------------------------------------------------------------------------
 # configuration options related to source browsing
 #---------------------------------------------------------------------------

include/plist/plist.h

diff --git a/include/plist/plist.h b/include/plist/plist.h
index 426e34f..46aca16 100644
--- a/include/plist/plist.h
+++ b/include/plist/plist.h
@@ -90,7 +90,7 @@
 #include <stdio.h>
 
     /**
-     * \mainpage libplist : A library to handle Apple Property Lists
+     * libplist : A library to handle Apple Property Lists
      * \defgroup PublicAPI Public libplist API
      */
     /*@{*/