Documentation: framebuffer: update documentation to current state ...

Framebuffer console support was added in 2015.

Reported-by: TobSnyder at #barebox irc
Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

video: implement framebuffer console ...

This patch realizes framebuffer console support for barebox. It
supports colors and enough escape sequences to show the barebox
console and editor properly.

fbconsole mini-HOWTO
====================

1. compile sandbox barebox with

    CONFIG_VIDEO=y
    CONFIG_FRAMEBUFFER_CONSOLE=y
    CONFIG_DRIVER_VIDEO_SDL=y

2. run barebox

3. test fbconsole

    fbconsole0.active=oe

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Documentation: Add new sphinxs docs ...

This is a rewrite of the Documentation in reStructuredText format using
Sphinx as build system, see http://sphinx-doc.org/.

The documentation is built into static html pages with 'make docs'.
The pages can be found under Documentation/html after building.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>