--HG--
rename : src/video/SDL_glfuncs.h => src/render/opengl/SDL_glfuncs.h

This compiles, but it untested.

attached is a working directfb driver diff which works with the current
changes. There are a number of changes around it as well, e.g.
configure.in.

The directfb renderdriver right now still depends on a some "includes"
from src/video/directfb. That's why it is not yet moved to the new
render folder.

--HG--
rename : src/render/direct3d/SDL_d3drender.c => src/render/direct3d/SDL_render_d3d.c
rename : src/render/opengl/SDL_renderer_gl.c => src/render/opengl/SDL_render_gl.c
rename : src/render/opengles/SDL_renderer_gles.c => src/render/opengles/SDL_render_gles.c
rename : src/render/software/SDL_renderer_sw.c => src/render/software/SDL_render_sw.c
rename : src/render/software/SDL_renderer_sw_c.h => src/render/software/SDL_render_sw_c.h

--HG--
extra : rebase_source : 8f8bc7a40ab9772086b227ac608b436af048d18a

Added a hint to determine whether framebuffer texture acceleration should be used, and added default behaviors for the various platforms.

This actually ends up being faster than Direct3D with a dynamic texture. (???)

Also experimented with dynamic textures, but didn't get any speed increase with them.  More research and testing is needed.

Also experimented with texture rectangle updates, but I think at this point the full rect update gives the most consistent results.

Switched the SDL 1.2 compatibility to use the window surface, so it's fast even when there's no hardware acceleration available.
This means that the YUV overlay now uses software, but that's okay since fast YUV code should be using the textures now anyway.