doc: migrate from SGML to restructuredtext

This is a great move to help contributors in maintaining documentation.

While doing huge changes in this area, do a bit more than simply SGML to rst:

 * move README from markdown to rst
 * make a "true" man page with no more information
 * refactor content and sections

Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

docs/Makefile

@@ -0,0 +1,24 @@
+# This program is free software under the terms of the GNU General Public
+# License. See the COPYING file which must come with this package.
+
+SOURCES = $(wildcard *.rst)
+HTML_TARGETS = $(patsubst %.rst,%.html,$(SOURCES))
+
+RM = rm
+
+all: html
+
+html: $(HTML_TARGETS)
+
+$(HTML_TARGETS): %.html : %.rst
+	rst2html.py $? $@
+
+man: offlineimap.1
+
+offlineimap.1: MANUAL.rst
+	rst2man.py MANUAL.rst offlineimap.1
+	cp -f offlineimap.1 ..
+
+clean:
+	$(RM) -f $(HTML_TARGETS)
+	$(RM) -f offlineimap.1 ../offlineimap.1