text: add bblit text-renderer

text: add bblit text-renderer

The bblit text-renderer is the most basic renderer which simply blits or
blends the glyphs into the framebuffer memory. It cannot be used with
displays that do not provide framebuffer access but only 3D access.
However, 3D rendering is currently broken, anyway, so we can ignore it.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>