doc: include README as mainpage

doxygen supports markdown so we can expand the README with general interesting
information in markdown format and have it be the front page of the
documentation at the same time.

This requires renaming README to README.txt, but that's a relatively small
price to pay.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>

README.txt

@@ -1,4 +1,7 @@
+/*!@mainpage
+
 libinput
+========
 
 libinput is a library that handles input devices for display servers and other
 applications that need to directly deal with input devices.
@@ -23,3 +26,5 @@ https://bugs.freedesktop.org/enter_bug.cgi?product=Wayland
 
 Online API documentation:
 http://wayland.freedesktop.org/libinput/doc/latest/modules.html
+
+*/

doc/Makefile.am

@@ -5,7 +5,8 @@ if HAVE_DOXYGEN
 noinst_DATA = html/index.html
 
 header_files = \
-	$(top_srcdir)/src/libinput.h
+	$(top_srcdir)/src/libinput.h \
+	$(top_srcdir)/README.txt
 
 html/index.html: libinput.doxygen $(header_files)
 	$(AM_V_GEN)$(DOXYGEN) $<

doc/libinput.doxygen.in

@@ -753,7 +753,8 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @top_srcdir@/src/libinput.h
+INPUT                  = @top_srcdir@/src/libinput.h \
+			 @top_srcdir@/README.txt
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses

src/libinput.h

@@ -35,13 +35,6 @@ extern "C" {
 	__attribute__ ((format (printf, _format, _args)))
 #define LIBINPUT_ATTRIBUTE_DEPRECATED __attribute__ ((deprecated))
 
-/**
- * @mainpage
- * libinput is a generic input device handling library. It abstracts
- * commonly-used concepts such as keyboard, pointer and touchpad handling
- * behind an API.
- */
-
 /**
  * @page tpbuttons Touchpad button behavior
  *